diff options
| author | peter <peter@FreeBSD.org> | 1996-12-31 19:51:17 +0000 |
|---|---|---|
| committer | peter <peter@FreeBSD.org> | 1996-12-31 19:51:17 +0000 |
| commit | b13db018fbb01d60dabb34ce9bd3f06994fd81b7 (patch) | |
| tree | a2327c4e40b3c074798fd7f0ddd86f66879ceab5 /contrib/bind/doc/misc | |
| parent | 2d3cf9fcaf1ca2528c5fe3ba683d1f6c1268dc41 (diff) | |
| download | FreeBSD-src-b13db018fbb01d60dabb34ce9bd3f06994fd81b7.zip FreeBSD-src-b13db018fbb01d60dabb34ce9bd3f06994fd81b7.tar.gz | |
Import Paul Vixie/ISC's bind-4.9.5-patch1 onto the vendor branch.
This has some (all?) of the DNSSEC key management/distribution mechanism
in place. (The SIG and KEY RR's)
Obtained from: Paul Vixie / ISC / ftp.isc.org
Diffstat (limited to 'contrib/bind/doc/misc')
| -rw-r--r-- | contrib/bind/doc/misc/FAQ.1of2 | 1823 | ||||
| -rw-r--r-- | contrib/bind/doc/misc/FAQ.2of2 | 1449 |
2 files changed, 1851 insertions, 1421 deletions
diff --git a/contrib/bind/doc/misc/FAQ.1of2 b/contrib/bind/doc/misc/FAQ.1of2 index ab55bea..e1d7c0a 100644 --- a/contrib/bind/doc/misc/FAQ.1of2 +++ b/contrib/bind/doc/misc/FAQ.1of2 @@ -1,382 +1,513 @@ Newsgroups: comp.protocols.tcp-ip.domains,comp.answers,news.answers -Path: vixie!news1.digital.com!uunet!in1.uu.net!usc!rutgers!njitgw.njit.edu!hertz.njit.edu!cdp2582 -From: cdp@njit.edu (Chris Peckham) +Path: vixie!news1.digital.com!su-news-hub1.bbnplanet.com!cpk-news-hub1.bbnplanet.com!news.bbnplanet.com!cam-news-hub1.bbnplanet.com!news.mathworks.com!news.kei.com!uhog.mit.edu!rutgers!njitgw.njit.edu!hertz.njit.edu!cdp2582 +From: cdp2582@hertz.njit.edu (Chris Peckham) Subject: comp.protocols.tcp-ip.domains Frequently Asked Questions (FAQ) (Part 1 of 2) -Message-ID: <cptd-faq-1-810621452@njit.edu> +Message-ID: <cptd-faq-1-849940949@njit.edu> Followup-To: comp.protocols.tcp-ip.domains Originator: cdp2582@hertz.njit.edu Keywords: BIND,DOMAIN,DNS Sender: news@njit.edu -Supersedes: <cptd-faq-1-807632375@njit.edu> +Supersedes: <cptd-faq-1-847336183@njit.edu> Nntp-Posting-Host: hertz.njit.edu -X-Posting-Frequency: posted on the 1st of each month +X-Posting-Frequency: posted during the first week of each month Reply-To: domain-faq@njit.edu (comp.protocols.tcp-ip.domains FAQ comments) Organization: NJIT.EDU - New Jersey Institute of Technology, Newark, NJ, USA -Date: Sat, 9 Sep 1995 04:37:47 GMT +Date: Sat, 7 Dec 1996 06:42:36 GMT Approved: news-answers-request@MIT.EDU -Expires: Sat 14 Oct 95 00:37:32 EDT -Lines: 1319 -Xref: vixie comp.protocols.tcp-ip.domains:6018 comp.answers:13881 news.answers:49918 +Expires: Sat 11 Jan 97 02:42:29 EDT +Lines: 1582 +Xref: vixie comp.protocols.tcp-ip.domains:12904 comp.answers:22440 news.answers:85682 Posted-By: auto-faq 3.1.1.2 Archive-name: internet/tcp-ip/domains-faq/part1 -Revision: 1.6 1995/05/12 18:49:48 +Revision: 1.14 1996/12/07 06:42:05 -This FAQ is edited and maintained by Chris Peckham, <cdp@njit.edu>. -The latest version may always be found for anonymous ftp from +Note that this posting has been split into two parts because of its size. - ftp://rtfm.mit.edu/pub/usenet/news.answers/internet/tcp-ip/domains-faq - ftp://ftp.njit.edu/pub/dns/Comp.protocols.tcp-ip.domains.FAQ +$Id: FAQ.1of2,v 8.4 1996/12/18 04:09:47 vixie Exp $ + +A new version of this document appears monthly. If this copy is more +than a month old it may be out of date. + +This FAQ is edited and maintained by Chris Peckham, <cdp@pfmc.net>. The +most recently posted version may be found for anonymous ftp from + +rtfm.mit.edu : /pub/usenet/news.answers/internet/tcp-ip/domains-faq + +It is also available in HTML from +http://www.users.pfmc.net/~cdp/cptd-faq/. If you can contribute any answers for items in the TODO section, please do -so by sending e-mail to domain-faq@njit.edu ! If you know of any items that -are not included and you feel that they should be, send the relevant -information to domain-faq@njit.edu. - - ------------------------------- - -Date: Fri May 12 14:41:47 EDT 1995 -Subject: Table of Contents - -Table of Contents -================= -Part 1 ------- - 0. TO DO - 1. INTRODUCTION / MISCELLANEOUS - 1.1 What is this newsgroup ? - 1.2 More information - 1.3 What is BIND and where is the latest version of BIND ? - 1.4 How can I find the route between systems ? - 1.5 Finding the hostname if you have the tcp-ip address - 1.6 How to register a domain name - 1.7 Change of Domain name - 1.8 How memory and CPU does DNS use ? - 1.9 Other things to consider when planning your servers - 1.10 Proper way to get NS and reverse IP records into DNS - 1.11 How to get my address assign from NIC? - 1.12 Is there a block of private IP addresses I can use? - 1.13 Cache failed lookups - 1.14 What does an NS record really do ? - 1.15 DNS ports - 1.16 Obtaining the latest cache file - 2. UTILITIES - 2.1 Utilities to administer DNS zone files - 2.2 DIG - Domain Internet Groper - 2.3 DNS packet analyzer - 2.4 host - 2.5 Programming with DNS - 2.6 A source of information relating to DNS - 3. DEFINITIONS - 3.1 TCP/IP Host Naming Conventions - 3.2 Slaves and servers with forwarders - 3.3 When is a server authoritative? - 3.4 Underscore in host-/domain names - 3.5 Lame delegation - 3.6 What does opt-class field do? - 3.7 Top level domains - 3.8 Classes of networks - 3.9 What is CIDR ? - 3.10 What is the rule for glue ? - -Part 2 ------- - 4. CONFIGURATION - 4.1 Changing a Secondary server to a Primary - 4.2 How do I subnet a Class B Address ? - 4.3 Subnetted domain name service - 4.4 Recommended format/style of DNS files - 4.5 DNS on a system not connected to the Internet - 4.6 Multiple Domain configuration - 4.7 wildcard MX records - 4.8 How to identify a wildcard MX record - 4.9 Why are fully qualified domain names recommended ? - 4.10 Distributing load using named - 4.11 Order of returned records - 4.12 resolv.conf - 4.13 Delegating authority - 4.14 DNS instead of NIS on a Sun OS 4.1.x system - 5. PROBLEMS - 5.1 No address for root server - 5.2 Error - No Root Nameservers for Class XX - 5.3 Bind 4.9.x and MX querying? - 5.4 Some root nameservers don't know localhost - 5.5 MX records and CNAMES and separate A records for MX targets - 5.6 NS is a CNAME - 5.7 Nameserver forgets own A record - 5.8 General problems (core dumps !) - 5.9 malloc and DECstations - 6. ACKNOWLEDGEMENTS - ------------------------------- - -Date: Wed May 3 12:55:13 EDT 1995 -Subject: Q0 - TO DO list - - -* How to do an initial installation -* How to change service providers (what happens) -* Explain the difference between BIND (an implementation) and DNS (spec) -* Expand the slave/forward section of Q 3.2 -* Add a definition of a "private domain" in discussion (or cut it out) -* mention mail-to-news gateways for newsgroup, mailing lists, anonymous - ftp, etc in what is newsgroup section -* The evils of wildcard MX records - - - -------------------------------- +so by sending e-mail to <domain-faq@pfmc.net> ! If you know of any items +that are not included and you feel that they should be, send the +relevant information to <domain-faq@pfmc.net>. + +=============================================================================== + +Index + + Section 1. TO DO / UPDATES + Q1.1 Contributions needed + Q1.2 UPDATES / Changes since last posting + + Section 2. INTRODUCTION / MISCELLANEOUS + Q2.1 What is this newsgroup ? + Q2.2 More information + Q2.3 What is BIND ? + Q2.4 What is the difference between BIND and DNS ? + Q2.5 Where is the latest version of BIND located ? + Q2.6 How can I find the path taken between two systems/domains ? + Q2.7 How do you find the hostname given the TCP-IP address ? + Q2.8 How do I register a domain ? + Q2.9 How can I change the IP address of our server ? + Q2.10 Issues when changing your domain name + Q2.11 How memory and CPU does DNS use ? + Q2.12 Other things to consider when planning your servers + Q2.13 Proper way to get NS and reverse IP records into DNS + Q2.14 How do I get my address assigned from the NIC ? + Q2.15 Is there a block of private IP addresses I can use? + Q2.16 Does BIND cache negative answers (failed DNS lookups) ? + Q2.17 What does an NS record really do ? + Q2.18 DNS ports + Q2.19 What is the cache file + Q2.20 Obtaining the latest cache file + Q2.21 Selecting a nameserver/root cache + Q2.22 InterNIC and domain names + + Section 3. UTILITIES + Q3.1 Utilities to administer DNS zone files + Q3.2 DIG - Domain Internet Groper + Q3.3 DNS packet analyser + Q3.4 host + Q3.5 How can I use DNS information in my program? + Q3.6 A source of information relating to DNS + + Section 4. DEFINITIONS + Q4.1 TCP/IP Host Naming Conventions + Q4.2 What are slaves and forwarders ? + Q4.3 When is a server authoritative? + Q4.4 My server does not consider itself authoritative ! + Q4.5 NS records don't configure servers as authoritative ? + Q4.6 underscore in host-/domainnames + Q4.7 What is lame delegation ? + Q4.8 How can I see if the server is "lame" ? + Q4.9 What does opt-class field in a zone file do? + Q4.10 Top level domains + Q4.11 Classes of networks + Q4.12 What is CIDR ? + Q4.13 What is the rule for glue ? + + Section 5. CONFIGURATION + Q5.1 Changing a Secondary server to a Primary server ? + Q5.2 Moving a Primary server to another server + Q5.3 How do I subnet a Class B Address ? + Q5.4 Subnetted domain name service + Q5.5 Recommended format/style of DNS files + Q5.6 DNS on a system not connected to the Internet + Q5.7 Multiple Domain configuration + Q5.8 wildcard MX records + Q5.9 How do you identify a wildcard MX record ? + Q5.10 Why are fully qualified domain names recommended ? + Q5.11 Distributing load using named + Q5.12 Order of returned records + Q5.13 resolv.conf + Q5.14 How do I delegate authority for sub-domains ? + Q5.15 DNS instead of NIS on a Sun OS 4.1.x system + Q5.16 Patches to add functionality to BIND + Q5.17 How to serve multiple domains from one server + + Section 6. PROBLEMS + Q6.1 No address for root server + Q6.2 Error - No Root Nameservers for Class XX + Q6.3 Bind 4.9.x and MX querying? + Q6.4 Do I need to define an A record for localhost ? + Q6.5 MX records, CNAMES and A records for MX targets + Q6.6 Can an NS record point to a CNAME ? + Q6.7 Nameserver forgets own A record + Q6.8 General problems (core dumps !) + Q6.9 malloc and DECstations + Q6.10 Can't resolve names without a "." + Q6.11 Err/TO errors being reported + Q6.12 Why does swapping kill BIND ? + + Section 7. ACKNOWLEDGEMENTS + Q7.1 How is this FAQ generated ? + Q7.2 What formats are available ? + Q7.3 Contributors + +=============================================================================== + +Section 1. TO DO / UPDATES + + Q1.1 Contributions needed + Q1.2 UPDATES / Changes since last posting + +----------------------------------------------------------------------------- + +Question 1.1. Contributions needed + +Date: Fri Dec 6 00:40:00 EST 1996 + +* Expand the slave/forward section + +----------------------------------------------------------------------------- + +Question 1.2. UPDATES / Changes since last posting + +Date: Fri Dec 6 00:40:00 EST 1996 + +* The FAQ is now maintained in BFNN (Bizzare format with No Name). This + allows me to create ASCII, HTML, and GNU info (postscript coming soon) + from one source file. +* References to 4.9.4 changed to 4.9.5. +* memory/CPU usage question - removed uunet map reference. Not there... +* Minor edits of information and questions for new format. +* How do I delegate authority for sub-domains ? - edited answer + +=============================================================================== + +Section 2. INTRODUCTION / MISCELLANEOUS + + Q2.1 What is this newsgroup ? + Q2.2 More information + Q2.3 What is BIND ? + Q2.4 What is the difference between BIND and DNS ? + Q2.5 Where is the latest version of BIND located ? + Q2.6 How can I find the path taken between two systems/domains ? + Q2.7 How do you find the hostname given the TCP-IP address ? + Q2.8 How do I register a domain ? + Q2.9 How can I change the IP address of our server ? + Q2.10 Issues when changing your domain name + Q2.11 How memory and CPU does DNS use ? + Q2.12 Other things to consider when planning your servers + Q2.13 Proper way to get NS and reverse IP records into DNS + Q2.14 How do I get my address assigned from the NIC ? + Q2.15 Is there a block of private IP addresses I can use? + Q2.16 Does BIND cache negative answers (failed DNS lookups) ? + Q2.17 What does an NS record really do ? + Q2.18 DNS ports + Q2.19 What is the cache file + Q2.20 Obtaining the latest cache file + Q2.21 Selecting a nameserver/root cache + Q2.22 InterNIC and domain names + +----------------------------------------------------------------------------- + +Question 2.1. What is this newsgroup ? Date: Thu Dec 1 11:08:28 EST 1994 -Subject: Q1.1 - What is this newsgroup ? -comp.protocols.tcp-ip.domains is the usenet newsgroup for discussion -on issues relating to the Domain Name System (DNS). +comp.protocols.tcp-ip.domains is the usenet newsgroup for discussion on +issues relating to the Domain Name System (DNS). This newsgroup is not for issues directly relating to IP routing and addressing. Issues of that nature should be directed towards comp.protocols.tcp-ip. +----------------------------------------------------------------------------- -------------------------------- +Question 2.2. More information + +Date: Fri Dec 6 00:41:03 EST 1996 +You can find more information concerning DNS in the following places: -Date: Fri May 12 13:54:01 EDT 1995 -Subject: Q1.2 - More information +* The BOG (BIND Operations Guide) - in the BIND distribution +* The FAQ included with BIND 4.9.5 in doc/misc/FAQ +* DNS and BIND by Albitz and Liu (an O'Reilly & Associates Nutshell + handbook) +* A number of RFCs (920, 974, 1032, 1034, 1101, 1123, 1178, 1183, 1348, + 1535, 1536, 1537, 1591, 1706, 1712, 1713, 1912, 1918) +* The DNS Resources Directory (DNSRD) http://www.dns.net/dnsrd/ +* If you are having troubles relating to sendmail and DNS, you may wish to + refer to the USEnet newsgroup comp.mail.sendmail and/or the FAQ for that + newsgroup which may be found for anonymous ftp at rtfm.mit.edu : + /pub/usenet/news.answers/mail/sendmail-faq +* Information concerning some frequently asked questions relating to the + Internet (i.e., what is the InterNIC, what is an RFC, what is the IETF, + etc) may be found for anonymous ftp from ds.internic.net : /fyi/fyi4.txt + A version may also be obtained with the URL + gopher://ds.internic.net/00/fyi/fyi4.txt. +* Information on performing an initial installation of BIND may be found + using the DNS Resources Directory at + http://www.dns.net/dnsrd/docs/basic.txt +* Three other USEnet newsgroups: - You can find more information concerning DNS in the following places: - - * The BOG (BIND Operations Guide) - in the BIND distribution - * The FAQ included with bind4.9.3 doc/misc/FAQ - * DNS and BIND by Albitz and Liu (an O'Reilly & Associates Nutshell - handbook) - * A number of RFCs (920, 974, 1032, 1034, 1101, 1123, 1178, 1183, 1348, - 1535, 1536, 1537, 1591, 1706, 1712, 1713) - * The DNS Resource Directory (DNSRD) - http://www.dns.net/dnsrd - * If you are having troubles relating to sendmail and DNS, you may wish to - refer to the USEnet newsgroup comp.mail.sendmail and/or the FAQ for that - newsgroup - ftp://rtfm.mit.edu/pub/usenet/news.answers/mail/sendmail-faq - * Information concerning some frequently asked questions relating to - the Internet (i.e., what is the InterNIC, what is an RFC, what is the - IETF, etc) may be found for anonymous ftp from - ftp://ds.internic.net/fyi/fyi4.txt - A version may also be obtained with the URL - gopher://ds.internic.net/00/fyi/fyi4.txt - - -------------------------------- - -Date: Fri Aug 4 10:18:58 EDT 1995 -Subject: Q1.3 - What is BIND and where is the latest version of BIND ? - -Q: What is BIND ? - -A: From the BOG Introduction - - - The Berkeley Internet Name Domain (BIND) implements - an Internet name server for the BSD operating system. - The BIND consists of a server (or ``daemon'') and a - resolver library. A name server is a network service - that enables clients to name resources or objects and - share this information with other objects in the network. - This in effect is a distributed data base system for - objects in a computer network. BIND is fully integrated - into BSD (4.3 and later releases) network programs for - use in storing and retrieving host names and address. - The system administrator can configure the system to use - BIND as a replacement to the older host table lookup of - information in the network hosts file /etc/hosts. The - default configuration for BSD uses BIND. - -Q: Where is the latest non-beta version of BIND ? - -A: The latest non-beta version of BIND is version 4.9.2. This can be - found for anonymous ftp from - - ftp://gatekeeper.dec.com/pub/misc/vixie/4.9.2-940221.tar.gz - -Q: Where is the latest version of 4.9.3 located ? + * comp.protocols.dns.bind + * comp.protocols.dns.ops + * comp.protocols.dns.std -A: You can reference this URL: - - http://www.isc.org/isc/ - - At this time, the latest version of 4.9.3 may be found for anonymous ftp - from - - ftp://ftp.vix.com/pub/bind/testing/bind-4.9.3-BETA24.tar.gz +----------------------------------------------------------------------------- - You will need GNU zip, Larry Wall's patch program (if there are any - patch files), and a C compiler to get BIND running from the above - mentioned source. +Question 2.3. What is BIND ? - GNU zip is available for anonymous ftp from +Date: Tue Sep 10 23:15:58 EDT 1996 - ftp://prep.ai.mit.edu/pub/gnu/gzip-1.2.4.tar +From the BOG Introduction - - patch is available for anonymous ftp from +The Berkeley Internet Name Domain (BIND) implements an Internet name +server for the BSD operating system. The BIND consists of a server (or +``daemon'') and a resolver library. A name server is a network +service that enables clients to name resources or objects and share this +information with other objects in the network. This in effect is a +distributed data base system for objects in a computer network. BIND +is fully integrated into BSD (4.3 and later releases) network programs +for use in storing and retrieving host names and address. The system +administrator can configure the system to use BIND as a replacement to +the older host table lookup of information in the network hosts file +/etc/hosts. The default configuration for BSD uses BIND. - ftp://prep.ai.mit.edu/pub/gnu/patch-2.1.tar.gz +----------------------------------------------------------------------------- ------------------------------- +Question 2.4. What is the difference between BIND and DNS ? -Date: Mon Jan 2 13:27:27 EST 1995 -Subject: Q1.4 - How can I find the route between systems +Date: Tue Sep 10 23:15:58 EDT 1996 -Q: How can I find the path taken by packets between two systems/domains ? - -A: Get the source of the 'traceroute' command, compile it and install - it on your system. +(text provided by Andras Salamon) DNS is the Domain Name System, a set of +protocols for a distributed database that was originally designed to +replace /etc/hosts files. DNS is most commonly used by applications to +translate domain names of hosts to IP addresses. A client of the DNS is +called a resolver; resolvers are typically located in the application +layer of the networking software of each TCP/IP capable machine. Users +typically do not interact directly with the resolver. Resolvers query the +DNS by directing queries at name servers that contain parts of the +distributed database that is accessed by using the DNS protocols. In +common usage, `the DNS' usually refers just to the data in the database. - One version of this program with additional functionality may be found - for anonymous ftp from +BIND (Berkeley Internet Name Domain) is an implementation of DNS, both +server and client. Development of BIND is funded by the Internet Software +Consortium and is coordinated by Paul Vixie. BIND has been ported to +Windows NT and VMS, but is most often found on Unix. BIND source code is +freely available and very complex; most of the development on the DNS +protocols is based on this code; and most Unix vendors ship BIND-derived +DNS implementations. As a result, the BIND name server is the most widely +used name server on the Internet. In common usage, `BIND' usually refers +to the name server that is part of the BIND distribution, and sometimes to +name servers in general (whether BIND-derived or not). - ftp://ftp.nikhef.nl/pub/network/traceroute.tar.Z +----------------------------------------------------------------------------- - This package is mirrored at +Question 2.5. Where is the latest version of BIND located ? - ftp://ftp.njit.edu/pub/dns/nikhef/traceroute.tar.Z +Fri Dec 6 00:23:19 EST 1996 - Another version may be found for anonymous ftp from +This information may be found at http://www.vix.com/isc/bind.html - ftp://ftp.psc.edu/pub/net_tools/traceroute.tar +At this time, BIND version of 4.9.5 may be found for anonymous ftp from - ------------------------------- +ftp.vix.com : /pub/bind/release/4.9.5/bind-4.9.5-REL.tar.gz + +Other sites that officially mirror the BIND distribution are + +* bind.fit.qut.edu.au : /pub/bind +* ftp.funet.fi : /pub/unix/tcpip/dns/bind +* ftp.univ-lyon1.fr : /pub/mirrors/unix/bind +* ftp.oleane.net : /pub/mirrors/unix/bind +* ftp.ucr.ac.cr : /pub/Unix/dns/bind +* ftp.luth.se : /pub/unix/dns/bind/beta + +You may need GNU zip, Larry Wall's patch program (if there are any patch +files), and a C compiler to get BIND running from the above mentioned +source. + +GNU zip is available for anonymous ftp from + +prep.ai.mit.edu : /pub/gnu/gzip-1.2.4.tar + +patch is available for anonymous ftp from + +prep.ai.mit.edu : /pub/gnu/patch-2.1.tar.gz + +A version of BIND for Windows NT is available for anonymous ftp from + +ftp.vix.com : /pub/bind/release/4.9.5/contrib/ntdns495relbin.zip + +and + +ftp.vix.com : /pub/bind/release/4.9.5/contrib/ntbind495rel.zip + +----------------------------------------------------------------------------- + +Question 2.6. How can I find the path taken between two systems/domains ? + +Date: Fri Dec 6 00:10:31 EST 1996 + +On a Unix system, use traceroute. If it is not available to you, you may +obtain the source source for 'traceroute', compile it and install it on +your system. + +One version of this program with additional functionality may be found for +anonymous ftp from + +ftp.nikhef.nl : /pub/network/traceroute.tar.Z + +Another version may be found for anonymous ftp from + +ftp.psc.edu : /pub/net_tools/traceroute.tar + +----------------------------------------------------------------------------- + +Question 2.7. How do you find the hostname given the TCP-IP address ? Date: Thu Dec 1 09:55:24 EST 1994 -Subject: Q1.5 - Finding the hostname if you have the tcp-ip address -Q: Can someone tell me how can I find the name of the domain if I know the - tcp-ip address of the domain? Is there some kind of service for this? - -A: For an address a.b.c.d you can always do: - -% nslookup -> set q=ptr -> d.c.b.a.in-addr.arpa. +For an address a.b.c.d you can always do: - Most newer version of nslookup (since 4.8.3) will recognize an address, - so you can just say: + % nslookup + > set q=ptr + > d.c.b.a.in-addr.arpa. -% nslookup a.b.c.d - - DiG will work like this also: - -$ dig -x a.b.c.d +Most newer version of nslookup (since 4.8.3) will recognize an address, so +you can just say: - Host from the contrib/host from the bind distribution may also be used. + % nslookup a.b.c.d -------------------------------- - -Date: Fri Apr 28 13:16:32 EDT 1995 -Subject: Q1.6 - How to register a domain name +DiG will work like this also: -Q: I would like to register a domain. How do I do this ? Can a name be - reserved, or must we already have an IP address and be hooked up to the - Internet before obtaining a domain name? - -A: You can talk to your Internet Service Provider (ISP). They can submit - the registration for you. If you are not going to be directly - connected, they should be able to offer MX records for your domain - for mail delivery (so that mail sent to the new domain will be sent - to your "standard" account). In the case where the registration is - done by the organization itself, it still makes the whole process - much easier if the ISP is approached for secondary servers _before_ - the InterNIC is approached for registration. - - For information about making the registration yourself, look to the - InterNIC ! + % dig -x a.b.c.d - ftp://internic.net/templates/ - gopher://rs.internic.net/ - http://www.internic.net/infoguide.html - http://www.ripe.net - - You will need at least two domain name servers when you register your - domain. Many ISP's are willing to provide primary and/or secondary name - service for their customers. +host from the contrib/host from the bind distribution may also be used. + +----------------------------------------------------------------------------- + +Question 2.8. How do I register a domain ? - Many times, registration of a domain name can be initiated by sending - e-mail to the zone contact. You can obtain the contact in the - SOA record for the country, or in a whois server: +Date: Wed Sep 4 23:59:42 EDT 1996 + +You can talk to your Internet Service Provider (ISP). They can submit the +registration for you. If you are not going to be directly connected, they +should be able to offer MX records for your domain for mail delivery (so +that mail sent to the new domain will be sent to your "standard" account). +In the case where the registration is done by the organization itself, it +still makes the whole process much easier if the ISP is approached for +secondary servers _before_ the InterNIC is approached for registration. + +For information about making the registration yourself, look to the +InterNIC (or other similar organization). + +* anonymout ftp from internic.net : /templates +* gopher://rs.internic.net/ +* http://rs.internic.net/reg/reg-forms.html +* http://www.ripe.net/ + +You will need at least two domain name servers when you register your +domain. Many ISP's are willing to provide primary and/or secondary name +service for their customers. + +Please note that the InterNIC is now charging a fee for domain names in +the "COM", "ORG", and "NET". More information may be found from the +Internic at + +http://rs.internic.net/domain-info/fee-policy.html + +Many times, registration of a domain name can be initiated by sending +e-mail to the zone contact. You can obtain the contact in the SOA record +for the country, or in a whois server: $ nslookup -type=SOA fr. origin = ns1.nic.fr mail addr = nic.nic.fr ... - - The mail address to contact in this case is 'nic@nic.fr' (you must - substitute an '@' for the first dot in the mail addr field). - - An alternate method to obtain the e-mail address of the national NIC - is the 'whois' server at InterNIC. - You may be requested to make your request to another email address or - using a certain information template/application. +The mail address to contact in this case is 'nic@nic.fr' (you must +substitute an '@' for the first dot in the mail addr field). + +An alternate method to obtain the e-mail address of the national NIC is +the 'whois' server at InterNIC. + +You may be requested to make your request to another email address or +using a certain information template/application. + +----------------------------------------------------------------------------- + +Question 2.9. How can I change the IP address of our server ? + +Date: Sun May 5 22:46:28 EDT 1996 +(From Mark Andrews) Before the move. -------------------------------- +* Ensure you are running a modern nameserver. BIND 4.9.3-REL + Patch1 is a + good choice. +* Inform all your secondaries that you are going to change. Have them + install both the current and new addresses in their named.boot's. +* Drop the ttl of the A's associated with the nameserver to something + small (5 min is usually good). +* Drop the refesh and retry times of the zone containing the forward + records for the server. +* Configure the new reverse zone before the move and make sure it is + operational. +* On the day of the move add the new A record(s) for the server. Don't + forget to have these added to parent domains. You will look like you are + multihomed with one interface dead. + +Move the machine after gracefully terminating any other services it is +offering. Then, + +* Fixup the A's, ttl, refresh and retry counters. (If you are running an + all server EDIT out all references to the old addresses in the cache + files). +* Inform all the secondaries the move is complete. +* Inform the parents of all zones you are primary of the new NS/A pairs + for the relevent zones. +* Inform all the administators of zones you are secondaring that the + machine has moved. +* For good measure update the serial no for all zones you are primary for. + This will flush out old A's. + +----------------------------------------------------------------------------- + +Question 2.10. Issues when changing your domain name Date: Sun Nov 27 23:32:41 EST 1994 -Subject: Q1.7 - Change of Domain name - -Q: We are preparing for a change of our domain name: - abc.foobar.com -> foobar.net - - What are the tricks and caveats we should be aware of ? - -A: The forward zones are easy and there are a number of ways to do it. - One way is the following: - - Have a single db file for the 2 domains, and have a single machine - be the primary server for both abc.foobar.com and foobar.net. - - To resolve the host foo in both domains, use a single zone file which - merely uses this for the host: - + +If you are changing your domain name from abc.foobar.com to foobar.net, +the forward zones are easy and there are a number of ways to do it. One +way is the following: + +Have a single db file for the 2 domains, and have a single machine be the +primary server for both abc.foobar.com and foobar.net. + +To resolve the host foo in both domains, use a single zone file which +merely uses this for the host: + foo IN A 1.2.3.4 - - Use a "@" wherever the domain would be used ie for the SOA: + +Use a "@" wherever the domain would be used ie for the SOA: @ IN SOA (... - - Then use this pair of lines in your named.boot: + +Then use this pair of lines in your named.boot: primary abc.foobar.com db.foobar primary foobar.net db.foobar - - The reverse zones should either contain PTRs to both names, - or to whichever name you believe to be canonical currently. -------------------------------- +The reverse zones should either contain PTRs to both names, or to +whichever name you believe to be canonical currently. -Date: Fri Apr 28 13:52:20 EDT 1995 -Subject: Q1.8 - How memory and CPU does DNS use ? - -Q: How much memory and CPU does DNS use ? +----------------------------------------------------------------------------- + +Question 2.11. How memory and CPU does DNS use ? + +Date: Fri Dec 6 01:07:56 EST 1996 -A: It can use quite a bit ! The main thing that BIND needs is memory. - It uses very little CPU or network bandwidth. The main - considerations to keep in mind when planning are: +It can use quite a bit ! The main thing that BIND needs is memory. It +uses very little CPU or network bandwidth. The main considerations to +keep in mind when planning are: - 1) How many zones do you have and how large are they ? - 2) How many clients do you expect to serve and how active are they ? +* How many zones do you have and how large are they ? +* How many clients do you expect to serve and how active are they ? - As an example, here is a snapshot of memory usage from CSIRO Division - of Mathematics and Statistics, Australia +As an example, here is a snapshot of memory usage from CSIRO Division of +Mathematics and Statistics, Australia Named takes several days to stabalize its memory usage. Our main server stabalises at ~10Mb. It takes about 3 days to reach this size from 6 M at startup. This is under Sun OS 4.1.3U1. - As another example, here is the configuration of ns.uu.net (from late - 1994): +As another example, here is the configuration of ns.uu.net (from late +1994): ns.uu.net only does nameservice. It is running a version of BIND 4.9.3 on a Sun Classic with 96 MB of RAM, 220 MB of swap (remember @@ -384,22 +515,17 @@ A: It can use quite a bit ! The main thing that BIND needs is memory. running Sun OS 4.1.3_U1. Joseph Malcolm, of Alternet, states that named generally hovers at - 5-10% of the CPU, except after a reload, when it eats it all. He - also states that if you are interested in the network connectivity - around the system (ns.uu.net is located off of Falls-Church4), a - PostScript map is available for anonymous ftp from + 5-10% of the CPU, except after a reload, when it eats it all. - ftp://ftp.uu.net/uunet-info/alternet.map.ps +----------------------------------------------------------------------------- - -------------------------------- +Question 2.12. Other things to consider when planning your servers Date: Mon Jan 2 14:24:51 EST 1995 -Subject: Q1.9 - Other things to consider when planning your servers - - When making the plans to set up your servers, you may want to also - consider the following issues: - + +When making the plans to set up your servers, you may want to also +consider the following issues: + A) Server O/S limitations/capacities (which tend to be widely divergent from vendor to vendor) B) Client resolver behavior (even more widely divergent) @@ -424,147 +550,109 @@ Subject: Q1.9 - Other things to consider when planning your servers traffic among several machines strategically located, possibly larger ones, and/or subdividing your domain itself. There are many options, tradeoffs, and DNS architectural paradigms from which to choose. +----------------------------------------------------------------------------- - ------------------------------- +Question 2.13. Proper way to get NS and reverse IP records into DNS Date: Mon Jan 2 13:03:53 EST 1995 -Subject: Q1.10 - Proper way to get NS and reverse IP records into DNS - -Q: Reverse domain registration is separate from forward domain registration. - How do I get it updated ? - -A: Blocks of network addresses have been delegated by the InterNIC. Check - if your network a.b.c.0 is in such a block by using nslookup: +Reverse domain registration is separate from forward domain registration. +Blocks of network addresses have been delegated by the InterNIC. Check if +your network a.b.c.0 is in such a block by using nslookup: nslookup -type=soa c.b.a.in-addr.arpa. nslookup -type=soa b.a.in-addr.arpa. nslookup -type=soa a.in-addr.arpa. - One of the above should give you the information you are looking for - (the others will return with an error something like `*** No start of - authority (SOA) records available for ...') - This will give you the email address of the person to whom you should - address your change request. - - If none of these works, your network probably has not been delegated - by the InterNIC and you need to contact them directly. - - CIDR has meant that the registration is delegated, but registration - of in-addr.arpa has always been separate from forward zones - and - for good reason - in that the forward and reverse zones may have - different policies, contents etc, may be served by a different set - of nameservers, and exist at different times (usually only at point - of creation). There isn't a one-to-one mapping between the two, so - merging the registration would probably cause more problems than - people forgetting/not-knowing that they had to register in-addr.arpa - zones separately. For example, there are organizations that have - hundreds of networks and two or more domains, with a sprinkling of - machines from each network in each of the domains. +One of the above should give you the information you are looking for (the +others will return with an error something like `*** No start of authority +(SOA) records available for ...') This will give you the email address of +the person to whom you should address your change request. - -------------------------------- - -Date: Mon Jan 2 13:08:38 EST 1995 -Subject: Q1.11 - How to get my address assign from NIC ? +If none of these works, your network probably has not been delegated by +the InterNIC and you need to contact them directly. - -Q: Can anyone tell me how can I get the address from NIC? How many subnets - will NIC give to me? - -A: You should probably ask your Internet provider to give you an address. - These days, addresses are being distributed through the providers, - so that they can assign adjacent blocks of addresses to sites that - go through the same provider, to permit more efficient routing on - the backbones. - - Unless you have thousands of hosts, you probably won't be able to get a - class B these days. Instead, you can get a series of class C networks. - Large requests will be queried, so be ready to provide a network plan if - you ask for more than 16 class C networks. - - If you can't do this through your Internet provider, you can look for a - subnet registration form on rs.internic.net. See the answer in this FAQ - to the question "How to register a domain name" for a URL to these - forms. - -------------------------------- +CIDR has meant that the registration is delegated, but registration of +in-addr.arpa has always been separate from forward zones - and for good +reason - in that the forward and reverse zones may have different +policies, contents etc, may be served by a different set of nameservers, +and exist at different times (usually only at point of creation). There +isn't a one-to-one mapping between the two, so merging the registration +would probably cause more problems than people forgetting/not-knowing that +they had to register in-addr.arpa zones separately. For example, there +are organizations that have hundreds of networks and two or more domains, +with a sprinkling of machines from each network in each of the domains. -Date: Mon Jan 2 13:12:01 EST 1995 -Subject: Q1.12 -Is there a block of private IP addresses I can use? +----------------------------------------------------------------------------- +Question 2.14. How do I get my address assigned from the NIC ? -Q: Is there a block of private IP addresses I can use? - -A: This answer may be found in the FAQ for the newsgroup comp.dcom.sys.cisco - available for anonymous ftp from +Date: Fri Dec 6 01:11:34 EST 1996 - ftp://rtfm.mit.edu/pub/usenet/comp.dcom.sys.cisco +You should probably ask your Internet provider to give you an address. +These days, addresses are being distributed through the providers, so that +they can assign adjacent blocks of addresses to sites that go through the +same provider, to permit more efficient routing on the backbones. - There is a block of private IP addresses that you can use. However - whether you wish to do so is an issue of some debate. - - There are two RFCs which discuss this issue, and present opposing - views: - -1597 Address Allocation for Private Internets. Y. Rekhter, B. - Moskowitz, D. Karrenberg & G. de Groot. March 1994. (Format: - TXT=17430 bytes) - -1627 Network 10 Considered Harmful (Some Practices Shouldn't be - Codified). E. Lear, E. Fair, D. Crocker & T. Kessler. June 1994. - (Format: TXT=18823 bytes) - - Neither one of these RFCs is anything more than a set of informational - guidelines; they are *not* words to live by (remember that RFC stands - for Request For Comments). If you're seriously considering using - private IP addresses, please read them both. - - In any event, RFC 1597 documents the allocation of the following - addresses for use by ``private internets'': +Unless you have thousands of hosts, you probably won't be able to get a +class B these days. Instead, you can get a series of class C networks. +Large requests will be queried, so be ready to provide a network plan if +you ask for more than 16 class C networks. + +If you can't do this through your Internet provider, you can look for a +subnet registration form on rs.internic.net. See the answer in this FAQ +to the question "How do I register a domain" for a URL to these forms. + +----------------------------------------------------------------------------- + +Question 2.15. Is there a block of private IP addresses I can use? + +Date: Sun May 5 23:02:49 EDT 1996 + +Yes there is. Please refer to RFC 1918: + + 1918 Address Allocation for Private Internets. Y. Rekhter, B. + Moskowitz, D. Karrenberg, G. de Groot, & E. Lear. February 1996. + (Format: TXT=22270 bytes) +RFC 1918 documents the allocation of the following addresses for use by +``private internets'': + 10.0.0.0 - 10.255.255.255 172.16.0.0 - 172.31.255.255 192.168.0.0 - 192.168.255.255 - - Most importantly, it is vital that nothing using these addresses - should ever connect to the global Internet, or have plans to do so. - Please read the above RFCs before considering implementing such - a policy. +----------------------------------------------------------------------------- -------------------------------- +Question 2.16. Does BIND cache negative answers (failed DNS lookups) ? Date: Mon Jan 2 13:55:50 EST 1995 -Subject: Q1.13 - Cache failed lookups -Q: Does BIND cache negative answers (failed DNS lookups) ? +Yes, BIND 4.9.3 and more recent versions will cache negative answers. -A: Yes, BIND 4.9.3 will cache negative answers. +----------------------------------------------------------------------------- - -------------------------------- +Question 2.17. What does an NS record really do ? -Date: Fri Feb 10 15:35:07 EST 1995 -Subject: Q1.14 - What does an NS record really do ? +Date: Wed Sep 4 22:52:18 EDT 1996 -Q: What does a NS record really do ? +The NS records in your zone data file pointing to the zone's name servers +(as opposed to the servers of delegated subdomains) don't do much. +They're essentially unused, though they are returned in the authority +section of reply packets from your name servers. -A: The NS records in your zone data file pointing to the zone's name - servers (as opposed to the servers of delegated subdomains) don't do - much. They're essentially unused, though they are returned in the - authority section of reply packets from your name servers. +However, the NS records in the zone file of the parent domain are used to +find the right servers to query for the zone in question. These records +are more important than the records in the zone itself. -------------------------------- +----------------------------------------------------------------------------- -Date: Fri Feb 10 15:40:10 EST 1995 -Subject: Q1.15 - DNS ports +Question 2.18. DNS ports -Q: Does anyone out there have any information/experience on exactly which - TCP/UDP ports DNS uses to send and receive queries ? +Date: Fri Feb 10 15:40:10 EST 1995 -A: Use the following chart: +The following table shows what TCP/UDP ports DNS uses to send and receive +queries: Prot Src Dst Use udp 53 53 Queries between servers (eg, recursive queries) @@ -579,40 +667,36 @@ A: Use the following chart: Note: >1023 is for non-priv ports on Un*x clients. On other client types, the limit may be more or less. - Another point to keep in mind when designing filters for DNS is that a - DNS server uses port 53 both as the source and destination for it's - queries. So, a client queries an initial server from an unreserved - port number to UDP port 53. If the server needs to query another - server to get the required info, it sends a UDP query to that server - with both source and destination ports set to 53. The response is then - sent with the same src=53 dest=53 to the first server which then - responds to the original client from port 53 to the original source - port number. - - The point of all this is that putting in filters to only allow UDP - between a high port and port 53 will not work correctly, you must also - allow the port 53 to port 53 UDP to get through. - - Also, ALL versions of BIND use TCP for queries in some cases. The - original query is tried using UDP. If the response is longer than - the allocated buffer, the resolver will retry the query using a TCP - connection. If you block access to TCP port 53 as suggested above, - you may find that some things don't work. - - Newer version of BIND allow you to configure a list of IP addresses - from which to allow zone transfers. This mechanism can be used to - prevent people from outside downloading your entire namespace. +Another point to keep in mind when designing filters for DNS is that a DNS +server uses port 53 both as the source and destination for it's queries. +So, a client queries an initial server from an unreserved port number to +UDP port 53. If the server needs to query another server to get the +required info, it sends a UDP query to that server with both source and +destination ports set to 53. The response is then sent with the same +src=53 dest=53 to the first server which then responds to the original +client from port 53 to the original source port number. +The point of all this is that putting in filters to only allow UDP between +a high port and port 53 will not work correctly, you must also allow the +port 53 to port 53 UDP to get through. -------------------------------- +Also, ALL versions of BIND use TCP for queries in some cases. The +original query is tried using UDP. If the response is longer than the +allocated buffer, the resolver will retry the query using a TCP +connection. If you block access to TCP port 53 as suggested above, you +may find that some things don't work. +Newer version of BIND allow you to configure a list of IP addresses from +which to allow zone transfers. This mechanism can be used to prevent +people from outside downloading your entire namespace. -Date: Fri Apr 28 14:19:10 EDT 1995 -Subject: Q1.16 - Obtaining the latest cache file +----------------------------------------------------------------------------- -Q: What is the cache file and where can I obtain the latest version ? +Question 2.19. What is the cache file -A: From the "Name Server Operations Guide" +Date: Fri Dec 6 01:15:22 EST 1996 + +From the "Name Server Operations Guide" 6.3. Cache Initialization @@ -625,13 +709,27 @@ A: From the "Name Server Operations Guide" higher authorities. The location of this file is specified in the boot file. ... - A copy of the comments in the file available from the InterNIC follow: +----------------------------------------------------------------------------- + +Question 2.20. Obtaining the latest cache file + +Date: Fri Dec 6 01:15:22 EST 1996 + +If you have a version of dig running, you may obtain the information with +the command + + dig @a.root-servers.net. . ns + +A perl script to handle some possible problems when using this method +from behind a firewall and that can also be used to periodically obtain +the latest cache file was posted to comp.protocols.tcp-ip.domains during +early October, 1996. It was posted with the subject "Keeping db.cache +current". It is available at +http://www.users.pfmc.net/~cdp/cptd-faq/current_db_cache.txt. + +The latest cache file may also be obtained from the InterNIC via ftp or +gopher: - ; This file holds the information on root name servers needed to - ; initialize cache of Internet domain name servers - ; (e.g. reference this file in the "cache . <file>" - ; configuration file of BIND domain name servers). - ; ; This file is made available by InterNIC registration services ; under anonymous FTP as ; file /domain/named.root @@ -640,84 +738,142 @@ A: From the "Name Server Operations Guide" ; under menu InterNIC Registration Services (NSI) ; submenu InterNIC Registration Archives ; file named.root - ; - ; last update: Oct 5, 1994 - ; related version of root zone: 1994100500 - ; - If you have a version of dig running, you may obtain the information with - the command +----------------------------------------------------------------------------- - dig @ns.internic.net . ns - +Question 2.21. Selecting a nameserver/root cache -------------------------------- +Date: Mon Aug 5 22:54:11 EDT 1996 +Exactly how is the a root server selected from the root cache? Does the +resolver attempt to pick the closest host or is it random or is it via +sortlist-type workings? If the root server selected is not available (for +whatever reason), will the the query fail instead of attempting another +root server in the list ? -Date: Mon Jan 2 13:13:49 EST 1995 -Subject: Q2.1 - Utilities to administer DNS zone files - -Q: I am wondering if there are utilities available to ease the - administration of the zone files in the DNS. - -A: There are a few. Two common ones are h2n and makezones. Both are perl - scripts. h2n is used to convert host tables into zone data files. It - is available for anonymous ftp from +Every recursive BIND name server (that is, one which is willing to go out +and find something for you if you ask it something it doesn't know) will +remember the measured round trip time to each server it sends queries to. +If it has a choice of several servers for some domain (like "." for +example) it will use the one whose measured RTT is lowest. - ftp://ftp.uu.net/published/oreilly/nutshell/dnsbind/dns.tar.Z. - - makezones works from a single file that looks like a forward zone file, - with some additional syntax for special cases. It is included in the - current BIND distribution. The newest version is always available for - anonymous ftp from +Since the measured RTT of all NS RRs starts at zero (0), every one gets +tried one time. Once all have responded, all RTT's will be nonzero, and +the "fastest server" will get all queries henceforth, until it slows down +for some reason. + +To promote dispersion and good recordkeeping, BIND will penalize the RTT +by a little bit each time a server is reused, and it will penalize the RTT +a _lot_ if it ever has to retransmit a query. For a server to stay "#1", +it has to keep on answering quickly and consistently. + +Note that this is something BIND does that the DNS Specification does not +mention at all. So other servers, those not based on BIND, might behave +very differently. + +----------------------------------------------------------------------------- + +Question 2.22. InterNIC and domain names + +Date: Sun Jun 2 11:23:49 EDT 1996 + +The current InterNIC policy on what to do if someone wants to use a domain +name that is already in use may be found at + +rs.internic.net : /policy/internic/internic-domain-4.txt + +or + +http://rs.internic.net/domain-info/internic-domain-4.html. + +The following information was submitted by Carl Oppedahl +<oppedahl@patents.com> : + +If the jealous party happens to have a trademark registration, it is quite +likely that the domain name owner will lose the domain name, even if they +aren't infringing the trademark. This presents a substantial risk of loss +of a domain name on only 30 days' notice. Anyone who is the manager of an +Internet-connected site should be aware of this risk and should plan for +it. + +See "How do I protect myself from loss of my domain name?" at +http://www.patents.com/weblaw.sht#domloss. + +For an example of an ISP's battle to keep its domain name, see +http://www.patents.com/nsi.sht. + +A compendium of information on the subject may be found at +http://www.law.georgetown.edu/lc/internic/domain1.html. + +=============================================================================== + +Section 3. UTILITIES + + Q3.1 Utilities to administer DNS zone files + Q3.2 DIG - Domain Internet Groper + Q3.3 DNS packet analyser + Q3.4 host + Q3.5 How can I use DNS information in my program? + Q3.6 A source of information relating to DNS + +----------------------------------------------------------------------------- - ftp://ftp.cus.cam.ac.uk/pub/software/programs/DNS/makezones - - This package is mirrored at +Question 3.1. Utilities to administer DNS zone files - ftp://ftp.njit.edu/pub/dns/cus.cam.ac/makezones +Date: Wed Sep 4 22:53:53 EDT 1996 - More information may be found using the DNS Resource Directory +There are a few utilities available to ease the administration of zone +files in the DNS. - http://www.dns.net/dnsrd +Two common ones are h2n and makezones. Both are perl scripts. h2n is +used to convert host tables into zone data files. It is available for +anonymous ftp from +ftp.uu.net : /published/oreilly/nutshell/dnsbind/dns.tar.Z -------------------------------- +makezones works from a single file that looks like a forward zone file, +with some additional syntax for special cases. It is included in the +current BIND distribution. The newest version is always available for +anonymous ftp from + +ftp.cus.cam.ac.uk : /pub/software/programs/DNS/makezones + +More information may be found using the DNS Resources Directory + +http://www.dns.net/dnsrd/. + +----------------------------------------------------------------------------- + +Question 3.2. DIG - Domain Internet Groper Date: Thu Dec 1 11:09:11 EST 1994 -Subject: Q2.2 - DIG - Domain Internet Groper - -Q: Where can I find the latest version of DIG ? - -A: The latest and greatest, official, accept-no-substitutes version of DiG - is the one that comes with BIND. Get the latest kit. -------------------------------- +The latest and greatest, official, accept-no-substitutes version of the +Domain Internet Groper (DiG) is the one that comes with BIND. Get the +latest kit. -Date: Mon May 15 12:57:42 EDT 1995 -Subject: Q2.3 -DNS packet analyser +----------------------------------------------------------------------------- -Q: I'm looking for a Ethernet packet analyser of public domain or standard - (like tcpdump, snoop, packetman) that is able to determine DNS data - field protocol - -A: There is a free ethernet analyser called Ethload available for PC's - running DOS. The latest filename is ETHLD104.ZIP. It understands lots - of protocols including TCP/UDP. It'll look inside there and display - DNS/BOOTP/ICMP packets etc. (Ed. note: something nice for someone to - add to tcpdump ;^) ). Depending on the ethernet controller it's given - it'll perform slightly differently. It handles NDIS/Novell/Packet - drivers. It works best with Novell's promiscuous mode drivers. - A A SimTel mirror site should have the program available for anonymous - ftp. As an example, +Question 3.3. DNS packet analyser - ftp://oak.oakland.edu/SimTel/msdos/lan/ethld104.zip +Date: Wed Sep 4 23:43:57 EDT 1996 +There is a free ethernet analyser called Ethload available for PC's +running DOS. The latest filename is ETHLD104.ZIP. It understands lots of +protocols including TCP/UDP. It'll look inside there and display +DNS/BOOTP/ICMP packets etc. (Ed. note: something nice for someone to add +to tcpdump ;^) ). Depending on the ethernet controller it's given it'll +perform slightly differently. It handles NDIS/Novell/Packet drivers. It +works best with Novell's promiscuous mode drivers. A SimTel mirror site +should have the program available for anonymous ftp. One is -------------------------------- +ftp.coast.net : /SimTel/msdos/lan/ethld104.zip + +----------------------------------------------------------------------------- + +Question 3.4. host Date: Sun Dec 4 21:15:38 EST 1994 -Subject: Q2.4 - host A section from the host man page: @@ -738,289 +894,369 @@ A section from the host man page: numeric Internet addresses. 'host' is compatible with both BIND 4.9 and BIND 4.8 - + 'host' may be found in contrib/host in the BIND distribution. The latest version always available for anonymous ftp from - ftp://ftp.nikhef.nl/pub/network/host.tar.Z +ftp.nikhef.nl : /pub/network/host.tar.Z It may also be found for anonymous ftp from - ftp://ftp.uu.net/networking/ip/dns/host.tar.Z - -------------------------------- +ftp.uu.net : /networking/ip/dns/host.tar.Z + +----------------------------------------------------------------------------- + +Question 3.5. How can I use DNS information in my program? Date: Fri Feb 10 15:25:11 EST 1995 -Subject: Q2.5 - Programming with DNS -Q: How can I use DNS information in my program? - -A: It depends on precisely what you want to do: - - a) Consider whether you need to write a program at all. It may well - be easier to write a shell program (e.g. using awk or perl) to parse - the output of dig, host or nslookup. - - b) If all you need is names and addresses, there will probably be - system routines 'gethostbyname' and 'gethostbyaddr' to provide this - information. - - c) If you need more details, then there are system routines (res_query - and res_search) to assist with making and sending DNS queries. - However, these do not include a routine to parse the resulting answer - (although routines to assist in this task are provided). There is a - separate library available that will take a DNS response and unpick - it into its constituent parts, returning a C structure that can be - used by the program. The source for this library is available for - anonymous ftp from +It depends on precisely what you want to do: - ftp://hpux.csc.liv.ac.uk/hpux/Networking/Admin/resparse-* +* Consider whether you need to write a program at all. It may well be + easier to write a shell program (e.g. using awk or perl) to parse the + output of dig, host or nslookup. +* If all you need is names and addresses, there will probably be system + routines 'gethostbyname' and 'gethostbyaddr' to provide this + information. +* If you need more details, then there are system routines (res_query and + res_search) to assist with making and sending DNS queries. However, + these do not include a routine to parse the resulting answer (although + routines to assist in this task are provided). There is a separate + library available that will take a DNS response and unpick it into its + constituent parts, returning a C structure that can be used by the + program. The source for this library is available for anonymous ftp at + hpux.csc.liv.ac.uk : /hpux/Networking/Admin/resparse-1.2 -------------------------------- +----------------------------------------------------------------------------- +Question 3.6. A source of information relating to DNS -Date: Wed May 3 12:46:50 EDT 1995 -Subject: Q2.6 - A source of information relating to DNS +Date: Tue Nov 5 23:42:21 EST 1996 -Q: Where can I find utilities and tools to help me manage my zone files ? +You may find utilities and tools to help you manage your zone files +(including WWW front-ends) in the "tools" section of the DNS resources +directory: -A: There are several tools available. Please refer to the "tools" section - of the DNS resources directory: +http://www.dns.net/dnsrd/tools.html - http://www.dns.net/dnsrd/tools.html +There are also a number of IP management tools available. Data +Communications had an article on the subject in Sept/Oct of 1996. The +tools mentioned in the article and a few others may be found at the +following sites: +* IP Address management, http://www.accugraph.com +* IP-Track, http://www.on.com +* NetID, http://www.isotro.com +* QIP, http://www.quadritek.com +* UName-It, http://www.esm.com -------------------------------- +=============================================================================== +Section 4. DEFINITIONS -Date: Fri May 12 14:33:40 EDT 1995 -Subject: Q3.1 - TCP/IP Host Naming Conventions + Q4.1 TCP/IP Host Naming Conventions + Q4.2 What are slaves and forwarders ? + Q4.3 When is a server authoritative? + Q4.4 My server does not consider itself authoritative ! + Q4.5 NS records don't configure servers as authoritative ? + Q4.6 underscore in host-/domainnames + Q4.7 What is lame delegation ? + Q4.8 How can I see if the server is "lame" ? + Q4.9 What does opt-class field in a zone file do? + Q4.10 Top level domains + Q4.11 Classes of networks + Q4.12 What is CIDR ? + Q4.13 What is the rule for glue ? -Q: Is a guide available relating to naming systems ? +----------------------------------------------------------------------------- -A: One guide/resource is RFC 1178, "Choosing a Name for Your Computer", - which is available via anonymous FTP from +Question 4.1. TCP/IP Host Naming Conventions - ftp://ftp.internic.netrfc/rfc1178.txt - - RFCs (Request For Comments) are specifications and guidelines for how - many aspects of TCP/IP and the Internet (should) work. Most RFCs are - fairly technical documents, and some have semantics that are hotly - contested in the newsgroups. But a few, like RFC 1178, are actually - good to read for someone who's just starting along a TCP/IP path. +Date: Mon Aug 5 22:49:46 EDT 1996 - -------------------------------- +One guide that may be used when naming hosts is RFC 1178, "Choosing a Name +for Your Computer", which is available via anonymous FTP from + +ftp.internic.net : /rfc/rfc1178.txt + +RFCs (Request For Comments) are specifications and guidelines for how many +aspects of TCP/IP and the Internet (should) work. Most RFCs are fairly +technical documents, and some have semantics that are hotly contested in +the newsgroups. But a few, like RFC 1178, are actually good to read for +someone who's just starting along a TCP/IP path. + +----------------------------------------------------------------------------- + +Question 4.2. What are slaves and forwarders ? Date: Thu Dec 1 10:32:43 EST 1994 -Subject: Q3.2 - What are slaves and forwarders ? - -Q: What are slaves and forwarders ? - -A: "forwarders" is a list of NS records that are _prepended_ to a list - of NS records to query if the data is not available locally. This - allows a rich cache of records to be built up at a centralized - location. This is good for sites that have sporadic or very slow - connections to the Internet. (demand dial-up, for example) It's - also just a good idea for very large distributed sites to increase - the chance that you don't have to go off to the Internet to get an - IP address. (sometimes for addresses across the street!) - - "slave" modifies this to say to replace the list of NS records - with the forwarders entry, instead of prepending to it. This is - for firewalled environments, where the nameserver can't directly - get out to the Internet at all. - "slave" is meaningless (and invalid, in late-model BINDs) without - "forwarders". "forwarders" is an entry in named.boot, and therefore - applies only to the nameserver (not to resolvers). +"forwarders" is a list of NS records that are _prepended_ to a list of NS +records to query if the data is not available locally. This allows a rich +cache of records to be built up at a centralized location. This is good +for sites that have sporadic or very slow connections to the Internet. +(demand dial-up, for example) It's also just a good idea for very large +distributed sites to increase the chance that you don't have to go off to +the Internet to get an IP address. (sometimes for addresses across the +street!) + +"slave" modifies this to say to replace the list of NS records with the +forwarders entry, instead of prepending to it. This is for firewalled +environments, where the nameserver can't directly get out to the Internet +at all. + +"slave" is meaningless (and invalid, in late-model BINDs) without +"forwarders". "forwarders" is an entry in named.boot, and therefore +applies only to the nameserver (not to resolvers). + +----------------------------------------------------------------------------- -------------------------------- +Question 4.3. When is a server authoritative? Date: Mon Jan 2 13:15:13 EST 1995 -Subject: Q3.3 - When is a server authoritative? - - -Q: What criteria does a server use to determine if it is authoritative - for a domain? - -A: In the case of BIND: - 1) The server contains current data in files for the zone in - question (Data must be current for secondaries, as defined - in the SOA) - 2) The server is told that it is authoritative for the zone, by - a 'primary' or 'secondary' keyword in /etc/named.boot. - 3) The server does an error-free load of the zone. - -Q: I have set up a DNS where there is an SOA record for - the domain, but the server still does not consider itself - authoritative. (I used nslookup and set server=the correct machine.) - It seems to me that something is not matching up somewhere. I suspect - that this is because the service provider has not given us control - over the IP numbers in our own domain, and so while the machine listed - has an A record for an address, there is no corresponding PTR record. - -A: That's possible too, but is unrelated to the first question. - You need to be delegated a zone before outside people will start - talking to your server. However, a server can still be authoritative - for a zone even though it hasn't been delegated authority (it's just - that only the people who use that as their server will see the data). - - A server may consider itself non-authoritative even though it's a - primary if there is a syntax error in the zone (see point 3 above). -Q: I always believe that it was the NS record that defined authoritative - servers. +In the case of BIND: + +* The server contains current data in files for the zone in question (Data + must be current for secondaries, as defined in the SOA) +* The server is told that it is authoritative for the zone, by a 'primary' + or 'secondary' keyword in /etc/named.boot. +* The server does an error-free load of the zone. -A: Nope, delegation is a separate issue from authoritativeness. - You can still be authoritative, but not delegated. (you can also be - delegated, but not authoritative -- that's a "lame delegation") +----------------------------------------------------------------------------- -Q: We have had problems in the past from servers that were - authoritative (primary or secondary) but no NS, so other thought they - were not. Some resolvers get very confused when they get non- - authoritative data from the primary server. +Question 4.4. My server does not consider itself authoritative ! + +Date: Mon Jan 2 13:15:13 EST 1995 -A: Yes, that's a lame delegation. That's not caused by what you said, - but rather by a server which is _not_ authoritative for a zone, yet - someone else (the parent) is saying that a server is authoritative - (via the NS records). +The question was: + + What if I have set up a DNS where there is an SOA record for + the domain, but the server still does not consider itself + authoritative. (when using nslookup and set server=the correct machine.) + It seems that something is not matching up somewhere. I suspect + that this is because the service provider has not given us control + over the IP numbers in our own domain, and so while the machine listed + has an A record for an address, there is no corresponding PTR record. +With the answer: + + That's possible too, but is unrelated to the first question. + You need to be delegated a zone before outside people will start + talking to your server. However, a server can still be authoritative + for a zone even though it hasn't been delegated authority (it's just + that only the people who use that as their server will see the data). + + A server may consider itself non-authoritative even though it's a + primary if there is a syntax error in the zone (see the list in the + previous question). +----------------------------------------------------------------------------- - The set of NS records in the parent zone must be a subset of the - authoritative servers to avoid lame delegations. +Question 4.5. NS records don't configure servers as authoritative ? +Date: Fri Dec 6 16:13:34 EST 1996 -------------------------------- +Nope, delegation is a separate issue from authoritativeness. You can +still be authoritative, but not delegated. (you can also be delegated, +but not authoritative -- that's a "lame delegation") -Date: Fri Apr 28 13:26:37 EDT 1995 -Subject: Q3.4 - underscore in host-/domainnames +----------------------------------------------------------------------------- +Question 4.6. underscore in host-/domainnames -Q: I had a quick look on whether underscores are allowed in host- or - domainnames. +Date: Mon Aug 5 22:39:02 EDT 1996 +The question is "Are underscores are allowed in host- or domainnames" ? RFC 1033 allows them. RFC 1035 doesn't. RFC 1123 doesn't. dnswalk complains about them. - Which RFC is the final authority these days? -A: Actually RFC 1035 deals with names of machines or names of - mail domains. i.e "_" is not permitted in a hostname or on the - RHS of the "@" in local@domain. +Which RFC is the final authority these days? + +Actually RFC 1035 deals with names of machines or names of mail domains. +i.e "_" is not permitted in a hostname or on the RHS of the "@" in +local@domain. - Underscore is permitted where ever the domain is NOT one of - these types of addresses. +Underscore is permitted where ever the domain is NOT one of these types +of addresses. - In general the DNS mostly contains hostnames and mail domainnames. - This will change as new resource record types for authenticating DNS - queries start to appear. +In general the DNS mostly contains hostnames and mail domainnames. This +will change as new resource record types for authenticating DNS queries +start to appear. - The latest version of 'host' checks for illegal characters in A/MX - record names and the NS/MX target names. +The latest version of 'host' checks for illegal characters in A/MX record +names and the NS/MX target names. - After saying all of that, remember that RFC 1123 is a Required Internet - Standard (per RFC 1720), and RFC 1033 isn't. Even 1035 isn't a required - standard. Therefore, RFC 1123 wins, no contest. +After saying all of that, remember that RFC 1123 is a Required Internet +Standard (per RFC 1720), and RFC 1033 isn't. Even RFC 1035 isn't a +required standard. Therefore, RFC 1123 wins, no contest. +From RFC 1123, Section 2.1 -------------------------------- + 2.1 Host Names and Numbers -Date: Fri Dec 2 15:03:56 EST 1994 -Subject: Q3.5 - Lame delegation + The syntax of a legal Internet host name was specified in RFC-952 + [DNS:4]. One aspect of host name syntax is hereby changed: the + restriction on the first character is relaxed to allow either a + letter or a digit. Host software MUST support this more liberal + syntax. -Q: What is lame delegation ? + And described by Dave Barr in RFC1912: -A: Two things are required for a lame delegation: - 1) A nameserver X is delegated as authoritative for a zone. - 2) Nameserver X is not performing nameservice for that zone. + Allowable characters in a label for a host name are only ASCII + letters, digits, and the `-' character. Labels may not be all + numbers, but may have a leading digit (e.g., 3com.com). Labels must + end and begin only with a letter or digit. See [RFC 1035] and [RFC + 1123]. (Labels were initially restricted in [RFC 1035] to start with + a letter, and some older hosts still reportedly have problems with + the relaxation in [RFC 1123].) Note there are some Internet + hostnames which violate this rule (411.org, 1776.com). - Try to think of a lame delegation as a long-term condition, brought - about by a misconfiguration somewhere. Bryan Beecher's 1992 LISA - paper on lame delegations is good to read on this. The problem - really lies in misconfigured nameservers, not "lameness" brought - about by transient outages. The latter is common on the Internet - and hard to avoid, while the former is correctable. +Finally, one more piece of information (From Paul Vixie): - In order to be performing nameservice for a zone, it must have - (presumed correct) data for that zone, and it must be answering - authoritatively to resolver queries for that zone. (The AA bit is - set in the flags section) + RFC 1034 says only that domain names have characters in them, though it + says so with enough fancy and indirection that it's hard to tell exactly. - The "classic" lame delegation case is when nameserver X is delegated - as authoritative for domain Y, yet when you ask Y about X, it - returns non-authoritative data. + Generally, for second level domains (i.e., something you would get from + InterNIC or from the US Domain Registrar and probably other ISO 3166 + country code TLDs), RFC 952 is thought to apply. RFC 952 was about host + names rather than domain names, but the rules seemed good enough. - Here's an example that shows what happens most often (using dig, - dnswalk, and doc to find). + <domainname> ::= <hname> - Let's say the domain bogus.com gets registered at the NIC and they - have listed 2 primary name servers, both from their *upstream* - provider: + <hname> ::= <name>*["."<name>] + <name> ::= <let>[*[<let-or-digit-or-hyphen>]<let-or-digit>] +There has been a recent update on this subject which may be found in + +ftp.internic.net : /internet-drafts/draft-andrews-dns-hostnames-03.txt. + +----------------------------------------------------------------------------- + +Question 4.7. What is lame delegation ? + +Date: Mon Aug 5 22:45:02 EDT 1996 + +Two things are required for a lame delegation: + +* A nameserver X is delegated as authoritative for a zone. +* Nameserver X is not performing nameservice for that zone. + +Try to think of a lame delegation as a long-term condition, brought about +by a misconfiguration somewhere. Bryan Beecher's 1992 LISA paper on lame +delegations is good to read on this. The problem really lies in +misconfigured nameservers, not "lameness" brought about by transient +outages. The latter is common on the Internet and hard to avoid, while +the former is correctable. + +In order to be performing nameservice for a zone, it must have (presumed +correct) data for that zone, and it must be answering authoritatively to +resolver queries for that zone. (The AA bit is set in the flags section) + +The "classic" lame delegation case is when nameserver X is delegated as +authoritative for domain Y, yet when you ask Y about X, it returns +non-authoritative data. + +Here's an example that shows what happens most often (using dig, dnswalk, +and doc to find). + +Let's say the domain bogus.com gets registered at the NIC and they have +listed 2 primary name servers, both from their *upstream* provider: + bogus.com IN NS ns.bogus.com bogus.com IN NS upstream.com bogus.com IN NS upstream1.com - So the root servers have this info. But when the admins at - bogus.com actually set up their zone files they put something like: - +So the root servers have this info. But when the admins at bogus.com +actually set up their zone files they put something like: + bogus.com IN NS upstream.com bogus.com IN NS upstream1.com - So your name server may have the nameserver info cached (which it - may have gotten from the root). The root says "go ask ns.bogus.com" - since they are authoritative +So your name server may have the nameserver info cached (which it may have +gotten from the root). The root says "go ask ns.bogus.com" since they are +authoritative - This is usually from stuff being registered at the NIC (either - nic.ddn.mil or rs.internic.net), and then updated later, but the - folks who make the updates later never let the folks at the NIC know - about it. +This is usually from stuff being registered at the NIC (either nic.ddn.mil +or rs.internic.net), and then updated later, but the folks who make the +updates later never let the folks at the NIC know about it. -Q: How can I see if the server is "lame" ? +----------------------------------------------------------------------------- -A: Go to the authoritative servers one level up, and ask them who - they think is authoritative, and then go ask each one of those - delegees if they think that they themselves are authoritative. If any - responds "no", then you know who the lame delegation is, and who is - delegating lamely to them. You can then send off a message to the - administrators of the level above. +Question 4.8. How can I see if the server is "lame" ? - The 'lamers' script from Byran Beecher really takes care of all this - for you. It parses the lame delegation notices from BIND's syslog - and summarizes them for you. It may be found in the contrib section - of the latest BIND distribution. The latest version is available - for anonymous ftp from +Date: Mon Aug 5 22:45:02 EDT 1996 - ftp://terminator.cc.umich.edu/dns/lame-delegations/ +Go to the authoritative servers one level up, and ask them who they think +is authoritative, and then go ask each one of those delegees if they think +that they themselves are authoritative. If any responds "no", then you +know who the lame delegation is, and who is delegating lamely to them. +You can then send off a message to the administrators of the level above. - If you want to actively check for lame delegations, you can use 'doc' - and 'dnswalk'. You can check things manually with 'dig'. +The 'lamers' script from Byran Beecher really takes care of all this for +you. It parses the lame delegation notices from BIND's syslog and +summarizes them for you. It may be found in the contrib section of the +latest BIND distribution. The latest version is available for anonymous +ftp from -------------------------------- +terminator.cc.umich.edu : /dns/lame-delegations/ -Date: Thu Dec 1 11:10:39 EST 1994 -Subject: Q3.6 - What does opt-class field do? + If you want to actively check for lame delegations, you can use 'doc' +and 'dnswalk'. You can check things manually with 'dig'. + +The InterNIC recently announced a new lame delegation that will be in +effect on 01 October, 1996. Here is a summary: + +* After receipt/processing of a name registration template, and at random + intervals thereafter, the InterNIC will perform a DNS query via UDP + Port 53 on domain names for an SOA response for the name being + registered. +* If the query of the domain name returns a non-authoritative response + from all the listed name servers, the query will be repeated four times + over the next 30 days at random intervals approximately 7 days apart, + with notification to all listed whois and nameserver contacts of the + possible pending deletion. If at least one server answers correctly, + but one or more are lame, FYI notifications will be sent to all contacts + and checking will be discontinued. Additionally, e-mail notices will be + provided to the contact for the name servers holding the delegation to + alert them to the "lame" condition. Notifications will state explicitly + the consequences of not correcting the "lame" condition and will be + assigned a descriptive subject as follows: + + Subject: Lame Delegation Notice: DOMAIN_NAME + + The notification will include a timestamp for when the query was + performed. +* If, following 30 days, the name servers still provide no SOA response, + the name will be placed in a "hold" status and the DNS information will + no longer be propagated. The administrative contact will be notified by + postal mail and all whois contacts will be notified by e-mail, with + instructions for taking corrective action. +* Following 60 days in a "hold" status, the name will be deleted and made + available for reregistration. Notification of the final deletion will + be sent to the name server and domain name contacts listed in the NIC + database. + +----------------------------------------------------------------------------- + +Question 4.9. What does opt-class field in a zone file do? -Q: Just something I was wondering about: What does the opt-class - field in an name database do (the one that always says IN)? - What would happen if I put something else there instead? +Date: Thu Dec 1 11:10:39 EST 1994 -A: This field is the address class. From the BOG - +This field is the address class. From the BOG - ...is the address class; currently, only one class is supported: IN for internet addresses and other internet information. Limited support is included for the HS class, which is for MIT/Athena ``Hesiod'' information. +----------------------------------------------------------------------------- -------------------------------- - -Date: Fri Feb 10 14:49:54 EST 1995 -Subject: Q3.7 - Top level domains +Question 4.10. Top level domains +Date: Fri Dec 6 15:13:35 EST 1996 A section from RFC 1591: @@ -1033,12 +1269,35 @@ A section from RFC 1591: letter country codes from ISO-3166. It is extremely unlikely that any other TLDs will be created. -[ Ed note: the ISO-3166 country codes may be found for anonymous ftp from: +----- + +[ Ed note: the ISO-3166 country codes may be found for anonymous ftp +from: + +* ftp.isi.edu : /in-notes/iana/assignments/country-codes +* ftp.ripe.net : /iso3166-codes - ftp://ftp.isi.edu/in-notes/iana/assignments/country-codes - ftp://ftp.ripe.net/iso3166-codes ] +[ Ed note: Since the Internic started charging for registration services, +(and for other reasons) there are a number of groups that want to offer +an alternative to registering a domain under a "standard" TLD. More +information on some of these options may be found at: + +* http://www.alternic.net/ +* http://www.eu.org/ +* http://www.ml.org/mljoin.html + +You may participate in one of the discussions on iTLD proposals at + +* To sign up: http://www.newdom.com/lists +* Old postings: http://www.newdom.com/archive + +] + +----- + + ... Under each TLD may be created a hierarchy of names. Generally, under the generic TLDs the structure is very flat. That is, many organizations are registered directly under the TLD, and any further @@ -1208,43 +1467,44 @@ A section from RFC 1480: state-wide organizations, clubs, or domain parks. For example: <org-name>.GEN.<state-code>.US. - The application form for the US domain may be found for anonymous ftp - from: +The application form for the US domain may be found: - ftp://internic.net/templates/us-domain-template.txt +* for anonymous ftp from internic.net : /templates/us-domain-template.txt +* http://www.isi.edu/us-domain/ - The application form for the EDU, COM, NET, ORG, and GOV domains may be - found for anonymous ftp from: +The application form for the EDU, COM, NET, ORG, and GOV domains may be +found for anonymous ftp from: - ftp://internic.net/templates/domain-template.txt +internic.net : /templates/domain-template.txt - -------------------------------- +----------------------------------------------------------------------------- -Date: Sun Nov 27 23:32:41 EST 1994 -Subject: Q3.8 - Classes of networks +Question 4.11. Classes of networks -Q: I am just kind of curious to what exactly the differences in classes - of networks are (class A, B, C). - -A: An Internet Protocol (IP) address is 32 bit in length, divided into - two or three parts (the network address, the subnet address (if present), - and the host address. The subnet addresses are only present if the - network has been divided into subnetworks. The length of the network, - subnet, and host field are all variable. - - There are five different network classes. The leftmost bits indicate - the class of the network. - - # bits in # bits in - network host -Class field field Internet Protocol address in binary Ranges +Date: Wed Sep 4 22:59:27 EDT 1996 + +The usage of 'classes of networks' (class A, B, C) are historical and have +been replaced by CIDR blocks on the Internet. That being said... + +An Internet Protocol (IP) address is 32 bit in length, divided into two +or three parts (the network address, the subnet address (if present), and +the host address. The subnet addresses are only present if the network +has been divided into subnetworks. The length of the network, subnet, and +host field are all variable. + +There are five different network classes. The leftmost bits indicate the +class of the network. + + # of # of + bits in bits in + network host +Class field field Internet Protocol address in binary Ranges ============================================================================ - A 7 24 0NNNNNNN.HHHHHHHH.HHHHHHHH.HHHHHHHH 1-127.x.x.x - B 14 16 10NNNNNN.NNNNNNNN.HHHHHHHH.HHHHHHHH 128-191.x.x.x - C 22 8 110NNNNN.NNNNNNNN.NNNNNNNN.HHHHHHHH 192-223.x.x.x - D NOTE 1 1110xxxx.xxxxxxxx.xxxxxxxx.xxxxxxxx 224-239.x.x.x - E NOTE 2 11110xxx.xxxxxxxx.xxxxxxxx.xxxxxxxx 240-247.x.x.x + A 7 24 0NNNNNNN.HHHHHHHH.HHHHHHHH.HHHHHHHH 1-127.x.x.x + B 14 16 10NNNNNN.NNNNNNNN.HHHHHHHH.HHHHHHHH 128-191.x.x.x + C 22 8 110NNNNN.NNNNNNNN.NNNNNNNN.HHHHHHHH 192-223.x.x.x + D NOTE 1 1110xxxx.xxxxxxxx.xxxxxxxx.xxxxxxxx 224-239.x.x.x + E NOTE 2 11110xxx.xxxxxxxx.xxxxxxxx.xxxxxxxx 240-247.x.x.x where N represents part of the network address and H represents part of the host address. When the subnet address is defined, the needed bits @@ -1254,77 +1514,76 @@ Class field field Internet Protocol address in binary Ranges NOTE 2: Reserved for future use 127.0.0.1 is reserved for local loopback. - - Under the current arrangements, many class A IP numbers will not be - assigned whereas class C usage will be at a premium. - -------------------------------- +----------------------------------------------------------------------------- -Date: Fri Apr 28 13:31:24 EDT 1995 -Subject: Q3.9 - What is CIDR ? +Question 4.12. What is CIDR ? -Q: What is CIDR ? +Date: Tue Nov 5 23:47:29 EST 1996 -A: CIDR is "Classless Inter-Domain Routing (CIDR). From RFC1517: +CIDR is "Classless Inter-Domain Routing (CIDR). From RFC 1517: - ...Classless Inter-Domain Routing (CIDR) attempts to deal with + ...Classless Inter-Domain Routing (CIDR) attempts to deal with these problems by defining a mechanism to slow the growth of routing tables and reduce the need to allocate new IP network numbers. - Much more information may be obtained in RFCs 1467, 1517, 1518, 1520; - with primary reference 1519 +Much more information may be obtained in RFCs 1467, 1517, 1518, 1520; +with primary reference 1519. + +Also please see the CIDR FAQ at +* http://www.ibm.net.il/~hank/cidr.html +* http://www.rain.net/faqs/cidr.faq.html +* http://www.lab.unisource.ch/services/internet/direct/cidr.html -------------------------------- +----------------------------------------------------------------------------- +Question 4.13. What is the rule for glue ? Date: Fri Apr 28 13:31:24 EDT 1995 -Subject: Q3.10 - What is the rule for glue ? -Q: What is the rule for glue ? +A glue record is an A record for a name that appears on the right-hand +side of a NS record. So, if you have this: -A: A glue record is an A record for a name that appears on the right-hand - side of a NS record. So, if you have this: sub.foobar.com. IN NS dns.sub.foobar.com. dns.sub.foobar.com. IN A 1.2.3.4 - then the second record is a glue record (for the NS record above it). - - You need glue records when -- and only when -- you are delegating - authority to a nameserver that "lives" in the domain you are delegating - *and* you aren't a secondary server for that domain. - - In other words, in the example above, you need to add an A record - for dns.sub.foobar.com since it "lives" in the domain it serves. - This boot strapping information is necessary: How are you supposed - to find out the IP address of the nameserver for domain FOO if the - nameserver for FOO "lives" in FOO? - - If you have this NS record: - +then the second record is a glue record (for the NS record above it). + +You need glue records when -- and only when -- you are delegating +authority to a nameserver that "lives" in the domain you are delegating +*and* you aren't a secondary server for that domain. + +In other words, in the example above, you need to add an A record for +dns.sub.foobar.com since it "lives" in the domain it serves. This boot +strapping information is necessary: How are you supposed to find out the +IP address of the nameserver for domain FOO if the nameserver for FOO +"lives" in FOO? + +If you have this NS record: + sub.foobar.com. IN NS dns.xyz123.com. - you do NOT need a glue record, and, in fact, adding one is a very - bad idea. If you add one, and then the folks at xyz123.com change - the address, then you will be passing out incorrect data. - - Also, unless you actually have a machine called something.IN-ADDR.ARPA, - you will never have any glue records present in any of your "reverse" - files. +you do NOT need a glue record, and, in fact, adding one is a very bad +idea. If you add one, and then the folks at xyz123.com change the +address, then you will be passing out incorrect data. + +Also, unless you actually have a machine called something.IN-ADDR.ARPA, +you will never have any glue records present in any of your "reverse" +files. - There is also a sort of implicit glue record that can be useful (or - confusing :^) ). If the parent server (abc.foobar.com domain in example - above) is a secondary server for the child, then the A record will be - fetched from the child server when the zone transfer is done. The glue - is still there but it's a little different, it's in the ip address in - the named.boot line instead of explicitly in the data. In this case - you can leave out the explicit glue A record and leave the manually - configured "glue" in just the one place in the named.boot file. +There is also a sort of implicit glue record that can be useful (or +confusing :^) ). If the parent server (abc.foobar.com domain in example +above) is a secondary server for the child, then the A record will be +fetched from the child server when the zone transfer is done. The glue is +still there but it's a little different, it's in the ip address in the +named.boot line instead of explicitly in the data. In this case you can +leave out the explicit glue A record and leave the manually configured +"glue" in just the one place in the named.boot file. - RFC 1537 says it quite nicely: +RFC 1537 says it quite nicely: 2. Glue records @@ -1337,3 +1596,7 @@ A: A glue record is an A record for a name that appears on the right-hand Old BIND versions ("native" 4.8.3 and older versions) showed the problem that wrong glue records could enter secondary servers in a zone transfer. + + +The remainder of the FAQ is in the next part (Part 2 of 2). + diff --git a/contrib/bind/doc/misc/FAQ.2of2 b/contrib/bind/doc/misc/FAQ.2of2 index ae453c9..40e1649 100644 --- a/contrib/bind/doc/misc/FAQ.2of2 +++ b/contrib/bind/doc/misc/FAQ.2of2 @@ -1,247 +1,227 @@ Newsgroups: comp.protocols.tcp-ip.domains,comp.answers,news.answers -Path: vixie!news1.digital.com!uunet!in1.uu.net!usc!rutgers!njitgw.njit.edu!hertz.njit.edu!cdp2582 -From: cdp@njit.edu (Chris Peckham) +Path: vixie!news1.digital.com!su-news-hub1.bbnplanet.com!news.bbnplanet.com!cam-news-hub1.bbnplanet.com!news.mathworks.com!news.kei.com!uhog.mit.edu!rutgers!njitgw.njit.edu!hertz.njit.edu!cdp2582 +From: cdp2582@hertz.njit.edu (Chris Peckham) Subject: comp.protocols.tcp-ip.domains Frequently Asked Questions (FAQ) (Part 2 of 2) -Message-ID: <cptd-faq-2-810621452@njit.edu> +Message-ID: <cptd-faq-2-849940949@njit.edu> Followup-To: comp.protocols.tcp-ip.domains Originator: cdp2582@hertz.njit.edu Keywords: BIND,DOMAIN,DNS Sender: news@njit.edu -Supersedes: <cptd-faq-2-807632375@njit.edu> +Supersedes: <cptd-faq-2-847336183@njit.edu> Nntp-Posting-Host: hertz.njit.edu -X-Posting-Frequency: posted on the 1st of each month +X-Posting-Frequency: posted during the first week of each month Reply-To: domain-faq@njit.edu (comp.protocols.tcp-ip.domains FAQ comments) Organization: NJIT.EDU - New Jersey Institute of Technology, Newark, NJ, USA -References: <cptd-faq-1-810621452@njit.edu> -Date: Sat, 9 Sep 1995 04:38:21 GMT +References: <cptd-faq-1-849940949@njit.edu> +Date: Sat, 7 Dec 1996 06:42:49 GMT Approved: news-answers-request@MIT.EDU -Expires: Sat 14 Oct 95 00:37:32 EDT -Lines: 1110 -Xref: vixie comp.protocols.tcp-ip.domains:6019 comp.answers:13882 news.answers:49919 +Expires: Sat 11 Jan 97 02:42:29 EDT +Lines: 1277 +Xref: vixie comp.protocols.tcp-ip.domains:12905 comp.answers:22441 news.answers:85683 Posted-By: auto-faq 3.1.1.2 Archive-name: internet/tcp-ip/domains-faq/part2 -Revision: 1.5 1995/05/12 18:50:41 - - -This FAQ is edited and maintained by Chris Peckham, <cdp@njit.edu>. -The latest version may always be found for anonymous ftp from - - ftp://rtfm.mit.edu/pub/usenet/news.answers/internet/tcp-ip/domains-faq - ftp://ftp.njit.edu/pub/dns/Comp.protocols.tcp-ip.domains.FAQ - -If you can contribute any answers for items in the TODO section, please do -so by sending e-mail to domain-faq@njit.edu ! If you know of any items that -are not included and you feel that they should be, send the relevant -information to domain-faq@njit.edu. - - ------------------------------- - -Date: Fri May 12 14:41:47 EDT 1995 -Subject: Table of Contents - -Table of Contents -================= -Part 1 ------- - 0. TO DO - 1. INTRODUCTION / MISCELLANEOUS - 1.1 What is this newsgroup ? - 1.2 More information - 1.3 What is BIND and where is the latest version of BIND ? - 1.4 How can I find the route between systems ? - 1.5 Finding the hostname if you have the tcp-ip address - 1.6 How to register a domain name - 1.7 Change of Domain name - 1.8 How memory and CPU does DNS use ? - 1.9 Other things to consider when planning your servers - 1.10 Proper way to get NS and reverse IP records into DNS - 1.11 How to get my address assign from NIC? - 1.12 Is there a block of private IP addresses I can use? - 1.13 Cache failed lookups - 1.14 What does an NS record really do ? - 1.15 DNS ports - 1.16 Obtaining the latest cache file - 2. UTILITIES - 2.1 Utilities to administer DNS zone files - 2.2 DIG - Domain Internet Groper - 2.3 DNS packet analyzer - 2.4 host - 2.5 Programming with DNS - 2.6 A source of information relating to DNS - 3. DEFINITIONS - 3.1 TCP/IP Host Naming Conventions - 3.2 Slaves and servers with forwarders - 3.3 When is a server authoritative? - 3.4 Underscore in host-/domain names - 3.5 Lame delegation - 3.6 What does opt-class field do? - 3.7 Top level domains - 3.8 Classes of networks - 3.9 What is CIDR ? - 3.10 What is the rule for glue ? - -Part 2 ------- - 4. CONFIGURATION - 4.1 Changing a Secondary server to a Primary - 4.2 How do I subnet a Class B Address ? - 4.3 Subnetted domain name service - 4.4 Recommended format/style of DNS files - 4.5 DNS on a system not connected to the Internet - 4.6 Multiple Domain configuration - 4.7 wildcard MX records - 4.8 How to identify a wildcard MX record - 4.9 Why are fully qualified domain names recommended ? - 4.10 Distributing load using named - 4.11 Order of returned records - 4.12 resolv.conf - 4.13 Delegating authority - 4.14 DNS instead of NIS on a Sun OS 4.1.x system - 5. PROBLEMS - 5.1 No address for root server - 5.2 Error - No Root Nameservers for Class XX - 5.3 Bind 4.9.x and MX querying? - 5.4 Some root nameservers don't know localhost - 5.5 MX records and CNAMES and separate A records for MX targets - 5.6 NS is a CNAME - 5.7 Nameserver forgets own A record - 5.8 General problems (core dumps !) - 5.9 malloc and DECstations - 6. ACKNOWLEDGEMENTS - ------------------------------- - -Date: Fri Dec 2 15:31:06 EST 1994 -Subject: Q4.1 - Changing a Secondary server to a Primary - -Q: Do I need to do anything special when I change a server from a secondary - to a primary ? - -A: For 4.8.3, it's prudent to kill and restart following any changes to - named.boot. - - In BIND 4.9.3, you only have to kill and restart named if you change - a primary zone to a secondary or v-v, or if you delete a zone and - remain authoritative for its parent. Every other case should be - taken care of by a HUP. (Ed. note: 4.9.3b9 may still require you to - kill and restart the server due to some bugs in the HUP code). +Revision: 1.13 1996/12/07 06:42:15 + + +(Continued from Part 1, where you'll find the introduction and +table of contents.) + + +=============================================================================== + +Section 5. CONFIGURATION + + Q5.1 Changing a Secondary server to a Primary server ? + Q5.2 Moving a Primary server to another server + Q5.3 How do I subnet a Class B Address ? + Q5.4 Subnetted domain name service + Q5.5 Recommended format/style of DNS files + Q5.6 DNS on a system not connected to the Internet + Q5.7 Multiple Domain configuration + Q5.8 wildcard MX records + Q5.9 How do you identify a wildcard MX record ? + Q5.10 Why are fully qualified domain names recommended ? + Q5.11 Distributing load using named + Q5.12 Order of returned records + Q5.13 resolv.conf + Q5.14 How do I delegate authority for sub-domains ? + Q5.15 DNS instead of NIS on a Sun OS 4.1.x system + Q5.16 Patches to add functionality to BIND + Q5.17 How to serve multiple domains from one server + +----------------------------------------------------------------------------- + +Question 5.1. Changing a Secondary server to a Primary server ? + +Date: Fri Jul 5 23:54:35 EDT 1996 + +For 4.8.3, it's prudent to kill and restart following any changes to +named.boot. + +In BIND 4.9.3, you only have to kill and restart named if you change a +primary zone to a secondary or v-v, or if you delete a zone and remain +authoritative for its parent. Every other case should be taken care of by +a HUP. (Ed. note: 4.9.3b9 may still require you to kill and restart the +server due to some bugs in the HUP code). + +You will also need to update the server information on the root servers. +You can do this by filing a new domain registration form to inform +InterNIC of the change. They will then update the root server's SOA +records. This process usually takes 10-12 business days after they +receive the request. + +----------------------------------------------------------------------------- - You will also need to update the server information on the root servers. - You can do this by filing a new domain registration form to inform - InterNIC of the change. They will then update the root server's SOA - records. This process usually takes 10-12 business days after they - receive the request. +Question 5.2. Moving a Primary server to another server -------------------------------- +Date: Fri Jul 5 23:54:35 EDT 1996 + +The usual solution is to move the primary to ns.newserver.com, and have +ns.oldserver.com be configured as a secondary server until the change to +the root servers takes place after the request has been made to the +InterNIC. + +If you are moving to a different ISP which will change your IP's, the +recommened setting for the SOA that would minimize problems for your name +servers using the old settings can be done as follows: + +Gradually lower the TTL value in your SOA (that's the last one of the five +numbers) to always be equal to the time left until you change over. +(assuming that none of your resource records have individual TTL's set, if +so, do likewise witht them.) So, the day before, lower to 43200 seconds +(12 hours). Then lower every few hours to be the time remaining until +the change-over. So, an hour before the change, you may just want to +lower it all the way to 60 seconds or so. That way no one can cache +information past the change-over. + +After the change, start gradually incrementing the TTL value, because +you'll probably be making changes to work out problems. Once everything +stabilizes, move the TTL up to whatever your normal values are. + +To minimize name servers from using the "old settings", you can do the +same thing with the "refresh" interval in the SOA (the second number of +the SOA). That will tell the secondaries to refresh every X seconds. +Lower that value as you approach the changeover date. You probably don't +want to go much below an hour or you'll start the primary thrashing as all +the secondaries perpetually refresh. + +Also see the answer to the "How can I change the IP address of our server +?" in the INTRODUCTION section. + +----------------------------------------------------------------------------- + +Question 5.3. How do I subnet a Class B Address ? Date: Fri Apr 28 13:34:52 EDT 1995 -Subject: Q4.2 - How do I subnet a Class B Address ? -Q: I just received a Class B internet address and I am wondering where to - get an RFC or other information on how to properly to the TCP/IP - sub-netting. - -A: That you need to subnet at all is something of a misconception. You - can also think of a class B network as giving you 65,534 individual - hosts, and such a network will work. You can also configure your - class B as 16,384 networks of 2 hosts each. That's obviously not - very practical, but it needs to be made clear that you are not - constrained by the size of an octet (remember that many older - devices would not work in a network configured in this manner). - - So, the question is: why do you need to subnet? One reason is that - it is easier to manage a subnetted network, and in fact, you can - delegate the responsibility for address space management to local - administrators on the various subnets. Also, IP based problems will - end up localized rather than affecting your entire network. - - If your network is a large backbone with numerous segments - individually branching off the backbone, that too suggests - subnetting. - - Subnetting can also be used to improve routing conditions. - - You may wish to partition your network to disallow certain protocols - on certain segments of your net. You can, for example, restrict IP or - IPX to certain segments only by adding a router routing high level - protocols, and across the router you may have to subnet. - - Finally, as far as how many subnets you need depends on the answer to - the above question. As far as subnet masks are concerned, the mask - can be anything from 255.0.0.0 to 255.255.255.252. You'll probably be - looking at 9 or 10 bits for the subnet (last octet 128 or 192 - respectively). RFC1219 discusses the issue of subnetting very well - and leaves the network administrator with a large amount of flexibility - for future growth. - - ------------------------------- - -Date: Sun Nov 27 23:32:41 EST 1994 -Subject: Q4.3 -Subnetted domain name service +That you need to subnet at all is something of a misconception. You can +also think of a class B network as giving you 65,534 individual hosts, and +such a network will work. You can also configure your class B as 16,384 +networks of 2 hosts each. That's obviously not very practical, but it +needs to be made clear that you are not constrained by the size of an +octet (remember that many older devices would not work in a network +configured in this manner). -Q: After doing some reading (DNS and BIND, Albitz&Liu), I don't really - find any examples of handling subnetted class C networks as separate - DNS domains. - -A: This is possible, just messy. You need to delegate down to the - fourth octet, so you will have one domain per IP address ! Here is - how you can subdelegate a in-addr.arpa address for non-byte aligned - subnet masks: +So, the question is: why do you need to subnet? One reason is that it is +easier to manage a subnetted network, and in fact, you can delegate the +responsibility for address space management to local administrators on the +various subnets. Also, IP based problems will end up localized rather +than affecting your entire network. - Take as an example the net 192.1.1.x, and example subnet mask - 255.255.255.240. - - We first define the domain for the class C net, - -$origin 1.1.192.in-addr.arpa -@ SOA (usual stuff) -@ ns some.nameserver - ns some.other.nameserver -; delegate a subdomain -one ns one.nameserver - ns some.nameserver -; delegate another -two ns two.nameserver - ns some.nameserver -; CNAME pointers to subdomain one -0 CNAME 0.one -1 CNAME 1.one -; through -15 CNAME 15.one -; CNAME pointers to subdomain two -16 CNAME 16.two -17 CNAME 17.two -31 CNAME 31.two -; CNAME as many as required. - - - Now, in the delegated nameserver, one.nameserver - -$origin one.1.1.192.in-addr.arpa -@ SOA (usual stuff) - NS one.nameserver - NS some.nameserver ; secondary for us -0 PTR onenet.one.domain -1 PTR onehost.one.domain -; through -15 PTR lasthost.one.domain - - And similar for the two.1.1.192.in-addr.arpa delegated domain. - - ------------------------------- +If your network is a large backbone with numerous segments individually +branching off the backbone, that too suggests subnetting. + +Subnetting can also be used to improve routing conditions. + +You may wish to partition your network to disallow certain protocols on +certain segments of your net. You can, for example, restrict IP or IPX to +certain segments only by adding a router routing high level protocols, +and across the router you may have to subnet. + +Finally, as far as how many subnets you need depends on the answer to the +above question. As far as subnet masks are concerned, the mask can be +anything from 255.0.0.0 to 255.255.255.252. You'll probably be looking at +9 or 10 bits for the subnet (last octet 128 or 192 respectively). RFC +1219 discusses the issue of subnetting very well and leaves the network +administrator with a large amount of flexibility for future growth. + +----------------------------------------------------------------------------- + +Question 5.4. Subnetted domain name service + +Date: Mon Aug 5 23:00:16 EDT 1996 + +If you are looking for some examples of handling subnetted class C +networks as separate DNS domains, see the Internet Draft + +draft-ietf-cidrd-classless-inaddr-02.txt + +for more information. This file is available for anonymous ftp at + +ds.internic.net : +/internet-drafts/draft-ietf-cidrd-classless-inaddr-02.txt + +or other IETF mirror sites (ftp.is.ca.za [Africa], nic.nordu.net [Europe], +munnari.oz.au [Pacific Rim], ds.internic.net [US East Coast], or +ftp.isi.edu [US West Coast]). + +Details follow- You need to delegate down to the fourth octet, so you will +have one domain per IP address ! Here is how you can subdelegate a +in-addr.arpa address for non-byte aligned subnet masks: + +Take as an example the net 192.1.1.x, and example subnet mask +255.255.255.240. + +We first define the domain for the class C net, + + $origin 1.1.192.in-addr.arpa + @ SOA (usual stuff) + @ ns some.nameserver + ns some.other.nameserver + ; delegate a subdomain + one ns one.nameserver + ns some.nameserver + ; delegate another + two ns two.nameserver + ns some.nameserver + ; CNAME pointers to subdomain one + 0 CNAME 0.one + 1 CNAME 1.one + ; through + 15 CNAME 15.one + ; CNAME pointers to subdomain two + 16 CNAME 16.two + 17 CNAME 17.two + 31 CNAME 31.two + ; CNAME as many as required. + +Now, in the delegated nameserver, one.nameserver + + $origin one.1.1.192.in-addr.arpa + @ SOA (usual stuff) + NS one.nameserver + NS some.nameserver ; secondary for us + 0 PTR onenet.one.domain + 1 PTR onehost.one.domain + ; through + 15 PTR lasthost.one.domain + +And similar for the two.1.1.192.in-addr.arpa delegated domain. + +There is additional documentation and a perl script that may be used for +this purpose available for anonymous ftp from: + +ftp.vix.com : /pub/bind/contrib/gencidrzone + +----------------------------------------------------------------------------- + +Question 5.5. Recommended format/style of DNS files Date: Sun Nov 27 23:32:41 EST 1994 -Subject: Q4.4 - Recommended format/style of DNS files -Q: Are there any suggestions for how to layout DNS configuration files - (both forward and reverse)? - -A: This answer is quoted from an article posted by Paul Vixie: - +This answer is quoted from an article posted by Paul Vixie: + I've gone back and forth on the question of whether the BOG should include a section on this topic. I know what I myself prefer, but I'm wary of ramming my own stylistic preferences down the throat of @@ -399,189 +379,174 @@ pc.home A 192.5.5.3 perl/tcl/awk/python tools) will help you maintain a consistent universe even if it's also a complex one. Editing by hand doesn't have to be deadly but you MUST take care. - ------------------------------- - + +----------------------------------------------------------------------------- + +Question 5.6. DNS on a system not connected to the Internet + Date: Sun Nov 27 23:32:41 EST 1994 -Subject: Q4.5 - DNS on a system not connected to the Internet - -Q: How do I use DNS on a system that is not connected to the Internet or - set BIND up with an internal root server ? - -A: You need to create your own root domain name server until you connect - to the internet. Your roots need to delegate to mydomain.com and any - in-addr.arpa subdomains you might have, and that's about it. As - soon as you're connected, rip out the fake roots and use the real - ones. - - It does not actually have to be another server pretending to be the root. - You can set up the name server so that it is primary for each domain - above you and leave them empty (i.e. you are foo.bar.com - claim to be - primary for bar.com and com) - -Q: What if you connect intermittently and want DNS to work when you are - connected, and "fail" when you are not ? - -A: You can point the resolver at the name server at the remote site and - if the connection (SLIP/PPP) isn't up, the resolver doesn't have a - route to the remote server and since there's only one name server in - resolv.conf, the resolver quickly backs off the using /etc/hosts. - No problem. You could do the same with multiple name server and a - resolver that did configurable /etc/hosts fallback. - ------------------------------- - +You need to create your own root domain name server until you connect to +the internet. Your roots need to delegate to mydomain.com and any +in-addr.arpa subdomains you might have, and that's about it. As soon as +you're connected, rip out the fake roots and use the real ones. + +It does not actually have to be another server pretending to be the root. +You can set up the name server so that it is primary for each domain above +you and leave them empty (i.e. you are foo.bar.com - claim to be primary +for bar.com and com) + +If you connect intermittently and want DNS to work when you are connected, +and "fail" when you are not, you can point the resolver at the name server +at the remote site and if the connection (SLIP/PPP) isn't up, the resolver +doesn't have a route to the remote server and since there's only one name +server in resolv.conf, the resolver quickly backs off the using +/etc/hosts. No problem. You could do the same with multiple name server +and a resolver that did configurable /etc/hosts fallback. + +----------------------------------------------------------------------------- + +Question 5.7. Multiple Domain configuration + Date: Fri Dec 2 15:40:49 EST 1994 -Subject: Q4.6 -Multiple Domain configuration - -Q: I have seen sites that seem to have multiple domain names pointing to the - same destination. I would like to implement this and have found no - information explaining how to do it. What I would like to do is: - +If you want to have multiple domain names pointing to the same +destination, such as: + ftp ftp.biff.com connects user to -> ftp.biff.com ftp ftp.fred.com connects user to -> ftp.biff.com ftp ftp.bowser.com connects user to -> ftp.biff.com - -A: This is done through CNAME records: - + +You may do this by using CNAMEs: + ftp.bowser.com. IN CNAME ftp.biff.com. - You can also do the same thing with multiple A records. - - ------------------------------- - +You can also do the same thing with multiple A records. + +----------------------------------------------------------------------------- + +Question 5.8. wildcard MX records + Date: Sun Nov 27 23:32:41 EST 1994 -Subject: Q4.7 - wildcard MX records -Q: Does BIND not understand wildcard MX records such as the following? - +Does BIND not understand wildcard MX records such as the following? + *.foo.com MX 0 mail.foo.com. - -A: Explicit RR's at one level of specificity will, by design, "block" a - wildcard at a lesser level of specificity. I suspect that you have - an RR (an A RR, perhaps?) for "bar.foo.com" which is blocking the - application of your "*.foo.com" wildcard. The initial MX query is - thus failing (NOERROR but an answer count of 0), and the backup - query finds the A RR for "bar.foo.com" and uses it to deliver the - mail directly (which is what you DIDN'T want it to do). Adding an - explicit MX RR for the host is therefore the right way to handle - this situation. - - See RFC 1034, Section 4.3.3 ("Wildcards") for more information on - this "blocking" behavior, along with an illustrative example. See - also RFC 974 for an explanation of standard mailer behavior in the - face of an "empty" response to one's MX query. - - Basically, what it boils down to is, there is no point in trying to - use a wildcard MX for a host which is otherwise listed in the DNS. - It just doesn't work. - ------------------------------- -Date: Thu Dec 1 11:10:39 EST 1994 -Subject: Q4.8 - How to identify a wildcard MX record +No. It just doesn't work. +Explicit RR's at one level of specificity will, by design, "block" a +wildcard at a lesser level of specificity. I suspect that you have an RR +(an A RR, perhaps?) for "bar.foo.com" which is blocking the application of +your "*.foo.com" wildcard. The initial MX query is thus failing (NOERROR +but an answer count of 0), and the backup query finds the A RR for +"bar.foo.com" and uses it to deliver the mail directly (which is what you +DIDN'T want it to do). Adding an explicit MX RR for the host is therefore +the right way to handle this situation. -Q: How do you identify a wildcard MX record ? +See RFC 1034, Section 4.3.3 ("Wildcards") for more information on this +"blocking" behavior, along with an illustrative example. See also RFC 974 +for an explanation of standard mailer behavior in the face of an "empty" +response to one's MX query. + +Basically, what it boils down to is, there is no point in trying to use a +wildcard MX for a host which is otherwise listed in the DNS. + +It just doesn't work. + +----------------------------------------------------------------------------- + +Question 5.9. How do you identify a wildcard MX record ? + +Date: Thu Dec 1 11:10:39 EST 1994 + +You don't really need to "identify" a wildcard MX RR. The precedence for +u@dom is: -A: You don't really need to "identify" a wildcard MX RR. The precedence - for u@dom is: - exact match MX exact match A wildcard MX - - One way to implement this is to query for ("dom",IN,MX) and if the - answer name that comes back is "*." something, you know it's a - wildcard, therefore you know there is no exact match MX, and you - therefore query for ("dom",IN,A) and if you get something, use it. - if you don't, use the previous wildcard response. - - RFC 974 explains this pretty well. - ------------------------------- + +One way to implement this is to query for ("dom",IN,MX) and if the answer +name that comes back is "*." something, you know it's a wildcard, +therefore you know there is no exact match MX, and you therefore query for +("dom",IN,A) and if you get something, use it. if you don't, use the +previous wildcard response. + +RFC 974 explains this pretty well. + +----------------------------------------------------------------------------- + +Question 5.10. Why are fully qualified domain names recommended ? Date: Sun Nov 27 23:32:41 EST 1994 -Subject: Q4.9 - Why are fully qualified domain names recommended ? - -Q: Why are fully qualified domain names recommended ? - -A: The documentation for BIND 4.9.2 says that the hostname should be set - to the full domain style name (i.e host.our.domain rather than - host). What advantages are there in this, and are there any adverse - consequences if we don't? - -A: Paul Vixie likes to do it :-) He lists a few reasons - - - * Sendmail can be configured to just use Dj$w rather than - Dj$w.mumble where "mumble" is something you have to edit in by - hand. Granted, most people use "mumble" elsewhere in their config - files ("tack on local domain", etc) but why should it be a - requirement ? - - * The real reason is that not doing it violates a very useful invariant: - +The documentation for BIND 4.9.2 says that the hostname should be set to +the full domain style name (i.e host.our.domain rather than host). What +advantages are there in this, and are there any adverse consequences if we +don't? + +Paul Vixie likes to do it :-) He lists a few reasons - + +* Sendmail can be configured to just use Dj$w rather than Dj$w.mumble + where "mumble" is something you have to edit in by hand. Granted, most + people use "mumble" elsewhere in their config files ("tack on local + domain", etc) but why should it be a requirement ? +* The real reason is that not doing it violates a very useful invariant: gethostbyname(gethostname) == gethostbyaddr(primary_interface_address) - - If you take an address and go "backwards" through the PTR's with - it, you'll get a FQDN, and if you push that back through the A - RR's, you get the same address. Or you should. Many multi-homed - hosts violate this uncaringly. - - If you take a non-FQDN hostname and push it "forwards" through the - A RR's, you get an address which, if you push it through the - PTR's, comes back as a FQDN which is not the same as the hostname - you started with. Consider the fact that, absent NIS/YP, there is - no "domainname" command analogous to the "hostname" command. - (NIS/YP's doesn't count, of course, since it's - sometimes-but-only-rarely the same as the Internet domain or - subdomain above a given host's name.) The "domain" keyword in - resolv.conf doesn't specify the parent domain of the current host; - it specifies the default domain of queries initiated on the - current host, which can be a very different thing. (As of RFC - 1535 and BIND 4.9.2's compliance with it, most people use "search" - in resolv.conf, which overrides "domain", anyway.) - - What this means is that there is NO authoritative way to - programmatically discover your host's FQDN unless it is set in the - hostname, or unless every application is willing to grovel the - "netstat -in" tables, find what it hopes is the primary address, - and do a PTR query on it. - - FQDN /bin/hostnames are, intuitively or not, the simplest way to go. - ------------------------------- + + If you take an address and go "backwards" through the PTR's with it, + you'll get a FQDN, and if you push that back through the A RR's, you get + the same address. Or you should. Many multi-homed hosts violate this + uncaringly. + + If you take a non-FQDN hostname and push it "forwards" through the A + RR's, you get an address which, if you push it through the PTR's, comes + back as a FQDN which is not the same as the hostname you started with. + Consider the fact that, absent NIS/YP, there is no "domainname" command + analogous to the "hostname" command. (NIS/YP's doesn't count, of + course, since it's sometimes-but-only-rarely the same as the Internet + domain or subdomain above a given host's name.) The "domain" keyword in + resolv.conf doesn't specify the parent domain of the current host; it + specifies the default domain of queries initiated on the current host, + which can be a very different thing. (As of RFC 1535 and BIND 4.9.2's + compliance with it, most people use "search" in resolv.conf, which + overrides "domain", anyway.) + + What this means is that there is NO authoritative way to + programmatically discover your host's FQDN unless it is set in the + hostname, or unless every application is willing to grovel the "netstat + -in" tables, find what it hopes is the primary address, and do a PTR + query on it. + + FQDN /bin/hostnames are, intuitively or not, the simplest way to go. + +----------------------------------------------------------------------------- + +Question 5.11. Distributing load using named Date: Wed Mar 1 11:04:43 EST 1995 -Subject: Q4.10 - Distributing load using named - -Q: If you attempt to distribute the load on a system using named, won't - the first response be cached, and then later queries use the cached - value? (This would be for requests that come through the same - server.) - -A: Yes. So it can be useful to use a lower TTL on records where this is - important. You can use values like 300 or 500 seconds. - If your local caching server has ROUND_ROBIN, it does not matter - what the authoritative servers have -- every response from the cache - is rotated. +When you attempt to distribute the load on a system using named, the first +response be cached, and then later queries use the cached value (This +would be for requests that come through the same server). Therefore, it +can be useful to use a lower TTL on records where this is important. You +can use values like 300 or 500 seconds. - But if it doesn't, and the authoritative server site is depending on - this feature (or the old "shuffle-A") to do load balancing, then if - one doesn't use small TTLs, one could conceivably end up with a - really nasty situation, e.g., hundreds of workstations at a branch - campus pounding on the same front end at the authoritative server's - site during class registration. +If your local caching server has ROUND_ROBIN, it does not matter what the +authoritative servers have -- every response from the cache is rotated. - Not nice. +But if it doesn't, and the authoritative server site is depending on this +feature (or the old "shuffle-A") to do load balancing, then if one doesn't +use small TTLs, one could conceivably end up with a really nasty +situation, e.g., hundreds of workstations at a branch campus pounding on +the same front end at the authoritative server's site during class +registration. -A: Paul Vixie has an example of the ROUND_ROBIN code in action. Here is - something that he wrote regarding his example: +Not nice. + +Paul Vixie has an example of the ROUND_ROBIN code in action. Here is +something that he wrote regarding his example: >I want users to be distributed evenly among those 3 hosts. @@ -613,46 +578,37 @@ A: Paul Vixie has an example of the ROUND_ROBIN code in action. Here is addresses you probably don't care and would just use a pile of CNAME's pointing directly at real host names. - {hydra.ugly.vix.com} + {hydra.ugly.vix.com name: hydra2.ugly.vix.com aliases: hydra.ugly.vix.com addresses: 10.2.0.2 10.2.0.3 10.2.0.1 - {hydra.ugly.vix.com} + {hydra.ugly.vix.com name: hydra3.ugly.vix.com aliases: hydra.ugly.vix.com addresses: 10.3.0.2 10.3.0.3 10.3.0.1 - {hydra.ugly.vix.com} + {hydra.ugly.vix.com name: hydra1.ugly.vix.com aliases: hydra.ugly.vix.com addresses: 10.1.0.2 10.1.0.3 10.1.0.1 - {hydra.ugly.vix.com} + {hydra.ugly.vix.com name: hydra2.ugly.vix.com aliases: hydra.ugly.vix.com addresses: 10.2.0.3 10.2.0.1 10.2.0.2 - {hydra.ugly.vix.com} + {hydra.ugly.vix.com name: hydra3.ugly.vix.com aliases: hydra.ugly.vix.com addresses: 10.3.0.3 10.3.0.1 10.3.0.2 - ------------------------------- - -Date: Sun Dec 4 22:12:32 EST 1994 -Subject: Q4.11 - Order of returned records +----------------------------------------------------------------------------- -Q: Is there any way to tell named to return records, specifically - address records, in the order in which they are listed in the - database? +Question 5.12. Order of returned records - It would appear that named consistently applies a sorting algorithm - to address records which seems to be virtually guaranteed to be - pessimal for our routers, which have many A records. +Sorting, is the *resolver's* responsibility. RFC 1123: -A: Sorting, is the *resolver's* responsibility. RFC 1123: 6.1.3.4 Multihomed Hosts @@ -672,19 +628,19 @@ A: Sorting, is the *resolver's* responsibility. RFC 1123: configuration information set by the system administrator. - In BIND 4.9.x's resolver code, the "sortlist" directive in resolv.conf - can be used to configure this. +In BIND 4.9.x's resolver code, the "sortlist" directive in resolv.conf +can be used to configure this. ------------------------------- +----------------------------------------------------------------------------- -Date: Fri Feb 10 15:46:17 EST 1995 -Subject: Q4.12 - resolv.conf +Question 5.13. resolv.conf +Date: Fri Feb 10 15:46:17 EST 1995 -Q: Why should I use "real" IP addresses in /etc/resolv.conf and not 0.0.0.0 - or 127.0.0.1. +The question was asked one time, "Why should I use 'real' IP addresses in +/etc/resolv.conf and not 0.0.0.0 or 127.0.0.1" ? -A: Paul Vixie writes on the issue of the contents of resolv.conf: +Paul Vixie writes on the issue of the contents of resolv.conf: It's historical. Some kernels can't unbind a UDP socket's source address, and some resolver versions (notably not including BIND @@ -714,41 +670,40 @@ A: Paul Vixie writes on the issue of the contents of resolv.conf: otherwise share identical copies of your resolv.conf on all the systems on any given subnet, not all of which will be servers. -A: The problem was with older versions of the resolver (4.8.X). If you - listed 127.0.0.1 as the first entry in resolv.conf, and for whatever - reason the local name server wasn't running and the resolver fell - back to the second name server listed, it would send queries to the - name server with the source IP address set to 127.0.0.1 (as it was - set when the resolver was trying to send to 127.0.0.1--you use the - loopback address to send to the loopback address). +The problem was with older versions of the resolver (4.8.X). If you +listed 127.0.0.1 as the first entry in resolv.conf, and for whatever +reason the local name server wasn't running and the resolver fell back to +the second name server listed, it would send queries to the name server +with the source IP address set to 127.0.0.1 (as it was set when the +resolver was trying to send to 127.0.0.1--you use the loopback address to +send to the loopback address). ------------------------------- +----------------------------------------------------------------------------- -Date: Mon Jan 2 13:50:13 EST 1995 -Subject: Q4.13 - Delegating authority +Question 5.14. How do I delegate authority for sub-domains ? -Q: How do I delegate authority for domains within my domain ? +Date: Sat Dec 7 02:04:17 EST 1996 + +When you start having a very big domain that can be broken into logical +and separate entities that can look after their own DNS information, you +will probably want to do this. Maintain a central area for the things +that everyone needs to see and delegate the authority for the other parts +of the organization so that they can manage themselves. + +Another essential piece of information is that every domain that exists +must have it NS records associated with it. These NS records denote the +name servers that are queried for information about that zone. For your +zone to be recognized by the outside world, the server responsible for the +zone above you must have created a NS record for your your new servers +(NOTE that the new servers DO NOT have to be in the new domain). For +example, putting the computer club onto the network and giving them +control over their own part of the domain space we have the following. + +The machine authorative for gu.uwa.edu.au is mackerel and the machine +authorative for ucc.gu.uwa.edu.au is marlin. + +in mackerel's data for gu.uwa.edu.au we have the following -A: When you start having a very big domain that can be broken into logical - and separate entities that can look after their own DNS information, - you will probably want to do this. Maintain a central area for the - things that everyone needs to see and delegate the authority for the - other parts of the organization so that they can manage themselves. - - Another essential piece of information is that every domain that - exists must have it NS records associated with it. These NS records - denote the name servers that are queried for information about that - zone. For your zone to be recognized by the outside world, the - server responsible for the zone above you must have created a NS - record for your machine in your domain. For example, putting the - computer club onto the network and giving them control over their - own part of the domain space we have the following. - - The machine authorative for gu.uwa.edu.au is mackerel and the machine - authorative for ucc.gu.uwa.edu.au is marlin. - - in mackerel's data for gu.uwa.edu.au we have the following - @ IN SOA ... IN A 130.95.100.3 IN MX mackerel.gu.uwa.edu.au. @@ -759,41 +714,118 @@ A: When you start having a very big domain that can be broken into logical ucc IN NS marlin.gu.uwa.edu.au. IN NS mackerel.gu.uwa.edu.au. - Marlin is also given an IP in our domain as a convenience. If they - blow up their name serving there is less that can go wrong because - people can still see that machine which is a start. You could place - "marlin.ucc" in the first column and leave the machine totally - inside the ucc domain as well. - - The second NS line is because mackerel will be acting as secondary name - server for the ucc.gu domain. Do not include this line if you are not - authorative for the information included in the sub-domain. +Marlin is also given an IP in our domain as a convenience. If they blow +up their name serving there is less that can go wrong because people can +still see that machine which is a start. You could place "marlin.ucc" in +the first column and leave the machine totally inside the ucc domain as +well. +The second NS line is because mackerel will be acting as secondary name +server for the ucc.gu domain. Do not include this line if you are not +authorative for the information included in the sub-domain. ------------------------------- +----------------------------------------------------------------------------- -Date: Wed Mar 1 11:45:00 EST 1995 -Subject: Q4.14 - DNS instead of NIS on a Sun OS 4.1.x system +Question 5.15. DNS instead of NIS on a Sun OS 4.1.x system -Q: I would appreciate any comments on whether running bind 4.9.x will - enable sendmail, ftp, telnet and other TCP/IP services to bypass - NIS and connect directly to named. - -A: How to do this is documented quite well in the comp.sys.sun.admin FAQ in - questions one and two. You can get them from: +Date: Sat Dec 7 01:14:17 EST 1996 - ftp://thor.ece.uc.edu/pub/sun-faq/FAQs/sun-faq.general - http://www.cis.ohio-state.edu/hypertext/faq/usenet/comp-sys-sun-faq +Comments relating to running bind 4.9.x on a Sun OS 4.1.x system and the +effect on sendmail, ftp, telnet and other TCP/IP services bypassing NIS +and directly using named is documented quite well in the +comp.sys.sun.admin FAQ in questions one and two. You can get them from: - as well as from rtfm.mit.edu in the usual place, etc. - +* ftp.ece.uc.edu : /pub/sun-faq/FAQs/sun-faq.general +* http://www.cis.ohio-state.edu/hypertext/faq/usenet/comp-sys-sun-faq ------------------------------- +as well as from rtfm.mit.edu in the usual place, etc. + +----------------------------------------------------------------------------- + +Question 5.16. Patches to add functionality to BIND + +Date: Tue Nov 5 23:53:47 EST 1996 + +There are others, but these are listed here: + +* When using the round robin DNS and assigning 3 IPs to a host (for + example), a process to guarantee that all 3 IPs are reachable may be + found at + http://www-leland.stanford.edu/~schemers/docs/lbnamed/lbnamed.html + +* Patches for 4.9.3-REL that will support the IPv6 AAAA record format may + be found at ftp.inria.fr : /network/ipv6/ + +* A patch for 4.9.3-REL that will allow you to turn off forwarding of + information from my server may be found at ftp.vix.com : + /pub/bind/release/4.9.3/contrib/noforward.tar.gz + +* How do I tell a server to listen to a particular interface to listen and + respond to DNS queries on ? + + Mark Andrews has a patch that will tell a 4.9.4 server to listen to a + particular interface and respond to DNS queries. It may be found at an + unofficial location: http://www.ultra.net/~jzp/andrews.patch.txt + +----------------------------------------------------------------------------- + +Question 5.17. How to serve multiple domains from one server + +Date: Tue Nov 5 23:44:02 EST 1996 + +Most name server implementations allow information about multiple domains +to be kept on one server, and questions about those domains to be +answered by that one server. For instance, there are many large servers +on the Internet that each serve information about more than 1000 +different domains. + +To be completely accurate, a server contains information about zones, +which are parts of domains that are kept as a single unit. [Ed note: for +a definition of zones and domains, see Section 2: The Name Service in the +"Name Server Operations Guide" included with the BIND 4.9.5 distribution.] + +In the configuration of the name server, the additional zones need to be +specified. An important consideration is whether a particular server is +primary or secondary for any specific zone--a secondary server maintains +only a copy of the zone, periodically refreshing its copy from another, +specified, server. In BIND, to set up a server as a secondary server for +the x.y.z zone, to the configuration file /etc/named.boot add the line + + secondary x.y.z 10.0.0.1 db.x.y.z + +where 10.0.0.1 is the IP address of the server that the zone will be +copied from, and db.x.y.z is a local filename that will contain the copy +of the zone. + +If this is a question related to how to set up multiple IP numbers on one +system, which you do not need to do to act as a domain server for +multiple domains, see + +http://www.thesphere.com/%7Edlp/TwoServers/. + +=============================================================================== + +Section 6. PROBLEMS + + Q6.1 No address for root server + Q6.2 Error - No Root Nameservers for Class XX + Q6.3 Bind 4.9.x and MX querying? + Q6.4 Do I need to define an A record for localhost ? + Q6.5 MX records, CNAMES and A records for MX targets + Q6.6 Can an NS record point to a CNAME ? + Q6.7 Nameserver forgets own A record + Q6.8 General problems (core dumps !) + Q6.9 malloc and DECstations + Q6.10 Can't resolve names without a "." + Q6.11 Err/TO errors being reported + Q6.12 Why does swapping kill BIND ? + +----------------------------------------------------------------------------- + +Question 6.1. No address for root server Date: Mon Jan 2 13:49:43 EST 1995 -Subject: Q5.1 - No address for root server - Q: I've been getting the following messages lately from bind-4.9.2.. ns_req: no address for root server @@ -803,27 +835,26 @@ We are behind a firewall and have the following for our named.cache file - . 99999999 IN NS POBOX.FOOBAR.COM. 99999999 IN NS FOOHOST.FOOBAR.COM. foobar.com. 99999999 IN NS pobox.foobar.com. - -A: You can't do that. Your nameserver contacts POBOX.FOOBAR.COM, gets the - correct list of root servers from it, then tries again and fails - because of your firewall. - - You will need a 'forwarder' definition, to ensure that all requests - are forwarded to a host which can penetrate the firewall. And - it is unwise to put phony data into 'named.cache'. - ------------------------------- +You can't do that. Your nameserver contacts POBOX.FOOBAR.COM, gets the +correct list of root servers from it, then tries again and fails because +of your firewall. + +You will need a 'forwarder' definition, to ensure that all requests are +forwarded to a host which can penetrate the firewall. And it is unwise to +put phony data into 'named.cache'. + +----------------------------------------------------------------------------- + +Question 6.2. Error - No Root Nameservers for Class XX Date: Sun Nov 27 23:32:41 EST 1994 -Subject: Q5.2 - Error - No Root Nameservers for Class XX Q: I've received errors before about "No root nameservers for class XX" but they've been because of network connectivity problems. I believe that Class 1 is Internet Class data. And I think I heard someone say that Class 4 is Hesiod?? Does anyone know what the various Class numbers are? - -A: From RFC 1700: +From RFC 1700: DOMAIN NAME SYSTEM PARAMETERS The Internet Domain Naming System (DOMAIN) includes several @@ -844,44 +875,37 @@ A: From RFC 1700: 65535 Reserved [PM1] DNS information for RFC 1700 was taken from +ftp.isi.edu : /in-notes/iana/assignments/dns-parameters - ftp://ftp.isi.edu/in-notes/iana/assignments/dns-parameters +Hesiod is class 4, and there are no official root nameservers for class 4, +so you can safely declare yourself one if you like. You might want to +put up a packet filter so that no one outside your network is capable of +making Hesiod queries of your machines, if you define yourself to be a +root nameserver for class 4. - Hesiod is class 4, and there are no official root nameservers for class - 4, so you can safely declare yourself one if you like. You might want - to put up a packet filter so that no one outside your network is capable - of making Hesiod queries of your machines, if you define yourself to be - a root nameserver for class 4. +----------------------------------------------------------------------------- + +Question 6.3. Bind 4.9.x and MX querying? ------------------------------- - Date: Sun Nov 27 23:32:41 EST 1994 -Subject: Q5.3 - Bind 4.9.x and MX querying? - -Q: If I query a 4.9.x DNS server for MX records, a list of the MX records - as well as a list of the authorative nameservers is returned. Why ? - -A: Bind 4.9.2 returns the list of nameserver that are authorative - for a domain in the response packet, along with their IP - addresses in the additional section. - ------------------------------- +If you query a 4.9.x DNS server for MX records, a list of the MX records +as well as a list of the authorative nameservers is returned. This +happens because bind 4.9.2 returns the list of nameserver that are +authorative for a domain in the response packet, along with their IP +addresses in the additional section. -Date: Sat Sep 9 00:36:01 EDT 1995 -Subject: Q5.4 - Some root nameservers don't know localhost +----------------------------------------------------------------------------- + +Question 6.4. Do I need to define an A record for localhost ? -Q: Do I need to define an A record for localhost ? +Date: Sat Sep 9 00:36:01 EDT 1995 - Where is the A record for 127.0.0.1 defined? I see where - the PTR record is defined pointing to localhost, but can't find - where the A record is. And is the A record supposed to be - localhost.MY_DOMAIN or just localhost ? +Somewhere deep in the BOG (BIND Operations Guide) that came with 4.9.3 +(section 5.4.3), it says that you define this yourself (if need be) in +the same zone files as your "real" IP addresses for your domain. Quoting +the BOG: -A: Somewhere deep in the BOG (BIND Operations Guide) that came with - 4.9.3 (section 5.4.3), it says that you define this yourself - (if need be) in the same zone files as your "real" IP addresses - for your domain. Quoting the BOG: ... As implied by this PTR record, there should be a ``localhost.my.dom.ain'' @@ -890,57 +914,54 @@ A: Somewhere deep in the BOG (BIND Operations Guide) that came with trailing dot when 1.0.0.127.in-addr.arpa is queried for;... - The sample files in the BIND distribution show you what needs to be - done (see the BOG). +The sample files in the BIND distribution show you what needs to be done +(see the BOG). - Some HP boxen (especially those running HP OpenView) will also need - "loopback" defined with this IP address. You may set it as a CNAME - record pointing to the "localhost." record. +Some HP boxen (especially those running HP OpenView) will also need +"loopback" defined with this IP address. You may set it as a CNAME +record pointing to the "localhost." record. + +----------------------------------------------------------------------------- + +Question 6.5. MX records, CNAMES and A records for MX targets ------------------------------- - Date: Sun Nov 27 23:32:41 EST 1994 -Subject: Q5.5 - MX records and CNAMES and separate A records for MX targets - -Q: The O'Reilly "DNS and Bind" book warns against using non-canonical - names in MX records, however, this warning is given in the context - of mail hubs that MX to each other for backup purposes. I don't see - how this applies to mail spokes. RFC 974 has a similar warning, but - I can not see where it specifically prohibits using an alias in an - MX record. - -A: Without the restrictions in the RFC, a MTA must request the A records - for every MX listed to determine if it is in the MX list then reduce - the list. This introduces many more lookups than would other wise be - required. If you are behind a 1200 bps link YOU DON'T WANT TO DO - THIS. The addresses associated with CNAMES are not passed as - additional data so you will force additional traffic to result even - if you are running a caching server locally. - - There is also the problem of how does the MTA find all of it's - IP addresses. This is not straight forward. You have to be able - to do this is you allow CNAMEs (or extra A's) as MX targets. - - The letter of the law is that an MX record should point to an A record. - - There is no "real" reason to use CNAMEs for MX targets or separate - As for nameservers any more. CNAMEs for services other than mail - should be used because there is no specified method for locating the - desired server yet. - - People don't care what the names of MX targets are. They're - invisible to the process anyway. If you have mail for "mary" - redirected to "sue" is totally irrelevant. Having CNAMEs as the - targets of MX's just needlessly complicates things, and is more work - for the resolver. - - Having separate A's for nameservers like "ns.your.domain" is - pointless too, since again nobody cares what the name of your - nameserver is, since that too is invisible to the process. If you - move your nameserver from "mary.your.domain" to "sue.your.domain" - nobody need care except you and your parent domain administrator - (and the InterNIC). Even less so for mail servers, since only you - are affected. + +The O'Reilly "DNS and Bind" book warns against using non-canonical names +in MX records, however, this warning is given in the context of mail hubs +that MX to each other for backup purposes. How does this apply to mail +spokes. RFC 974 has a similar warning, but where is it specifically +prohibited to us an alias in an MX record ? + +Without the restrictions in the RFC, a MTA must request the A records for +every MX listed to determine if it is in the MX list then reduce the list. +This introduces many more lookups than would other wise be required. If +you are behind a 1200 bps link YOU DON'T WANT TO DO THIS. The addresses +associated with CNAMES are not passed as additional data so you will force +additional traffic to result even if you are running a caching server +locally. + +There is also the problem of how does the MTA find all of it's IP +addresses. This is not straight forward. You have to be able to do this is +you allow CNAMEs (or extra A's) as MX targets. + +The letter of the law is that an MX record should point to an A record. + +There is no "real" reason to use CNAMEs for MX targets or separate As for +nameservers any more. CNAMEs for services other than mail should be used +because there is no specified method for locating the desired server yet. + +People don't care what the names of MX targets are. They're invisible to +the process anyway. If you have mail for "mary" redirected to "sue" is +totally irrelevant. Having CNAMEs as the targets of MX's just needlessly +complicates things, and is more work for the resolver. + +Having separate A's for nameservers like "ns.your.domain" is pointless +too, since again nobody cares what the name of your nameserver is, since +that too is invisible to the process. If you move your nameserver from +"mary.your.domain" to "sue.your.domain" nobody need care except you and +your parent domain administrator (and the InterNIC). Even less so for +mail servers, since only you are affected. Q: Given the example - @@ -968,7 +989,7 @@ A: This isn't what the BOG says at all. See below. You can have a CNAME Here's the relevant BOG snippet: - aliases {ttl} addr-class CNAME Canonical name + aliases {ttl addr-class CNAME Canonical name ucbmonet IN CNAME monet The Canonical Name resource record, CNAME, speci- @@ -981,12 +1002,14 @@ A: This isn't what the BOG says at all. See below. You can have a CNAME their value (e.g., NS or MX) must list the canoni- cal name, not the nickname. ------------------------------- - +----------------------------------------------------------------------------- + +Question 6.6. Can an NS record point to a CNAME ? + Date: Wed Mar 1 11:14:10 EST 1995 -Subject: Q5.6 - NS is a CNAME -Q: Can I do this ? Is it legal ? +Can I do this ? Is it legal ? + @ SOA (.........) NS ns.host.this.domain. @@ -994,43 +1017,39 @@ Q: Can I do this ? Is it legal ? ns CNAME third third IN A xxx.xxx.xxx.xxx +No. Only one RR type is allowed to refer, in its data field, to a CNAME, +and that's CNAME itself. So CNAMEs can refer to CNAMEs but NSs and MXs +cannot. -A: No. Only one RR type is allowed to refer, in its data field, to a - CNAME, and that's CNAME itself. So CNAMEs can refer to CNAMEs but - NSs and MXs cannot. - - BIND 4.9.3 (Beta11 and later) explicitly syslogs this case rather than - simply failing as pre-4.9 servers did. Here's a current example: +BIND 4.9.3 (Beta11 and later) explicitly syslogs this case rather than +simply failing as pre-4.9 servers did. Here's a current example: - Dec 7 00:52:18 gw named[17561]: \ - "foobar.com IN NS" points to a CNAME (foobar.foobar.com) + Dec 7 00:52:18 gw named[17561]: "foobar.com IN NS" \ + points to a CNAME (foobar.foobar.com) - Here is the reason why: +Here is the reason why: - Nameservers are not required to include CNAME records in the - Additional Info section returned after a query. It's partly an - implementation decision and partly a part of the spec. The - algorithm described in RFC 1034 (pp24,25; info also in RFC 1035, - section 3.3.11, p 18) says 'Put whatever addresses are available - into the additional section, using glue RRs [if necessary]'. - Since NS records are speced to contain only primary names of - hosts, not CNAMEs, then there's no reason for algorithm to - mention them. If, on the other hand, it's decided to allow CNAMEs - in NS records (and indeed in other records) then there's no - reason that CNAME records might not be included along with A - records. The Additional Info section is intended for any - information that might be useful but which isn't strictly the - answer to the DNS query processed. It's an implementation - decision in as much as some servers used to follow CNAMEs in - NS references. +Nameservers are not required to include CNAME records in the Additional +Info section returned after a query. It's partly an implementation +decision and partly a part of the spec. The algorithm described in RFC +1034 (pp24,25; info also in RFC 1035, section 3.3.11, p 18) says 'Put +whatever addresses are available into the additional section, using glue +RRs [if necessary]'. Since NS records are speced to contain only primary +names of hosts, not CNAMEs, then there's no reason for algorithm to +mention them. If, on the other hand, it's decided to allow CNAMEs in NS +records (and indeed in other records) then there's no reason that CNAME +records might not be included along with A records. The Additional Info +section is intended for any information that might be useful but which +isn't strictly the answer to the DNS query processed. It's an +implementation decision in as much as some servers used to follow CNAMEs +in NS references. +----------------------------------------------------------------------------- ------------------------------- +Question 6.7. Nameserver forgets own A record Date: Fri Dec 2 16:17:31 EST 1994 -Subject: Q5.7 - Nameserver forgets own A record - Q: Lately, I've been having trouble with named 4.9.2 and 4.9.3. Periodically, the nameserver will seem to "forget" its own A record, although the other information stays intact. One theory I had was @@ -1044,17 +1063,14 @@ A: This is invariably due to not removing ALL of the cached zones You get "ignoreds" because the primaries for the relevant zones are running old versions of BIND which pass out more glue than is required. named-xfer trims off this extra glue. - ------------------------------- -Date: Sun Dec 4 22:21:22 EST 1994 -Subject: Q5.8 - General problems (core dumps !) +----------------------------------------------------------------------------- -Q: I am running bind 4.9.3b9p1 on a DEC alpha OSF/1 V3.0 and have had it - core dump while in debug mode. The last lines printed to named.run - were [...] +Question 6.8. General problems (core dumps !) -A: Paul Vixie says: +Date: Sun Dec 4 22:21:22 EST 1994 + +Paul Vixie says: I'm always interested in hearing about cases where BIND dumps core. However, I need a stack trace. Compile with -g and not -O (unless @@ -1067,65 +1083,216 @@ A: Paul Vixie says: dump for a day or so in case I have questions you can answer via gdb/dbx. ------------------------------- +----------------------------------------------------------------------------- + +Question 6.9. malloc and DECstations Date: Mon Jan 2 14:19:22 EST 1995 -Subject: Q5.9 - malloc and DECstations -We have replaced malloc on our DECstations with a malloc that is more -compact in memory usage, and this helped the operation of bind a lot. -The source is now available for anonymous ftp from +We have replaced malloc on our DECstations with a malloc that is more +compact in memory usage, and this helped the operation of bind a lot. The +source is now available for anonymous ftp from - ftp://ftp.cs.wisc.edu/pub/misc/malloc.tar.gz - +ftp.cs.wisc.edu : /pub/misc/malloc.tar.gz + +----------------------------------------------------------------------------- + +Question 6.10. Can't resolve names without a "." + +(Answer written by Mark Andrews) You are not using a RFC 1535 aware +resolver. Depending upon the age of your resolver you could try adding a +search directive to resolv.conf. + + e.g. + domain <domain> + search <domain> [<domain2> ...] + +If that doesn't work you can configure you server to serve the parent and +grandparent domains as this is the default search list. + +"domain langley.af.mil" has an implicit "search langley.af.mil af.mil mil" +in the old resolvers, and you are timing out trying to resolve the +address with one of these domains tacked on. + +When resolving internic.net the following will be tried in order. + internic.net.langley.af.mil + internic.net.af.mil + internic.net.mil + internic.net. + +RFC 1535 aware resolvers try qualified address first. + + internic.net. + internic.net.langley.af.mil + internic.net.af.mil + internic.net.mil +RFC 1535 documents the problems associated with the old search +algorithim, including security issues, and how to alleviate some of the +problems. + +----------------------------------------------------------------------------- + +Question 6.11. Err/TO errors being reported + +Date: Sun May 5 23:46:32 EDT 1996 + +Why are errors like + + Apr 2 20:41:58 nameserver named[25846]: Err/TO getting serial# for + "foobar.domain1.com" + Apr 2 20:41:59 nameserver named[25846]: Err/TO getting serial# for + "foobar.domain2.com" + +reported ? These generally indicate that there is one of the following +problems: + +* A network problem between you and the primary, +* A bad IP address in named.boot, +* The primary is Lame for the zone. + +An external check to see if you can retrieve the SOA is the best way to +work out which it is. + +----------------------------------------------------------------------------- + +Question 6.12. Why does swapping kill BIND ? + +Date: Thu Jul 4 23:20:20 EDT 1996 + +The question was: + + I've been diagnosing a problem with BIND 4.9.x (where x is usually 3BETA9 + or 3REL) for several months now. I finally tracked it down to swap space + utilization on the unix boxes. + + This happens under (at least) under Linux 1.2.9 & 1.2.13, SunOS 4.1.3U1, + 4.1.1, and Solaris 2.5. The symptom is that if these machines get into + swap at all bind quits resolving most, if not all queries. Mind you that + these machines are not "swapping hard", but rather we're talking about a + several hundred K TEMPORARY deficiency. I have noticed while digging + through various archives that there is some referral to "bind thrashing + itself to death". Is this what is happening ? + +And the answer is: + + Yes it is. Bind can't tolerate having even a few pages swapped out. + The time required to send responses climbs to several seconds/request, + and the request queue fills and overflows. ------------------------------- - -Date: Fri Apr 28 13:56:32 EDT 1995 -Subject: Q6 - Acknowledgements - -Listed in e-mail address alphabetical order, the following people have -contributed to this FAQ: - -Benoit.Grange@inria.fr (Benoit.Grange) -D.T.Shield@csc.liv.ac.uk (Dave Shield) -adam@comptech.demon.co.uk (Adam Goodfellow) -andras@is.co.za (Andras Salamon) -barmar@nic.near.net (Barry Margolin) -barr@pop.psu.edu (David Barr) -bj@herbison.com (B.J. Herbison) -bje@cbr.fidonet.org (Ben Elliston) -brad@birch.ims.disa.mil (Brad Knowles) -ckd@kei.com (Christopher Davis) -cdp@hertz.njit.edu (Chris Peckham) -cricket@hp.com (Cricket Liu) -cudep@csv.warwick.ac.uk (Ian 'Vato' Dickinson [ID17]) -dparter@cs.wisc.edu (David Parter) -e07@nikhef.nl (Eric Wassenaar) -fwp@CC.MsState.Edu (Frank Peters) -gah@cco.caltech.edu (Glen A. Herrmannsfeldt) -glenn@popco.com (Glenn Fleishman) -harvey@indyvax.iupui.edu (James Harvey) -hubert@cac.washington.edu (Steve Hubert) -jmalcolm@uunet.uu.net (Joseph Malcolm) -jhawk@panix.com (John Hawkinson) -kevin@cfc.com (Kevin Darcy) -lamont@abstractsoft.com (Sean T. Lamont) -lavondes@tidtest.total.fr (Michel Lavondes) -mark@ucsalf.ac.uk (Mark Powell) -marka@syd.dms.CSIRO.AU (Mark Andrews) -mathias@unicorn.swi.com.sg (Mathias Koerber) -mjo@iao.ford.com (Mike O'Connor) -nick@flapjack.ieunet.ie (Nick Hilliard) -patrick@oes.amdahl.com (Patrick J. Horgan) -ph10@cus.cam.ac.uk (Philip Hazel) -rv@seins.Informatik.Uni-Dortmund.DE (Ruediger Volk) -shields@tembel.org (Michael Shields) -tanner@george.arc.nasa.gov (Rob Tanner) -vixie@vix.com (Paul A Vixie) -wag@swl.msd.ray.com (William Gianopoulos {84718}) -whg@inel.gov (Bill Gray) -wolf@pasteur.fr (Christophe Wolfhugel) + It's possible to shrink memory consumption a lot by undefining STATS + and XSTATS, and recompiling. You could nuke DEBUG too, which will + cut the code size down some, but probably not the data size. If that + doesn't do the job then it sounds like you'll need to move DNS onto a + separate box. + + BIND tends to touch all of its resident pages all of the time with + normal activity... if you look at the RSS verses the total process + size, you will always see the RSS within, usually, 90% of the total + size of the process. This means that *any* paging of named-owned + pages will stall named. Thus, a machine running a heavily accessed + named process cannot afford to swap *at all*. + + (Paul Vixie continues on this subject): + I plan to try to get BIND to exhibit slightly better locality of + reference in some future release. Of course, I can only do this if + the query names also exhibit some kind of hot spots. If someone + queries all your names often, BIND will have to touch all of its VM + pool that often. (Right now, BIND touches everything pretty often + even if you're just hammering on some hot spots -- that's the part + I'd like to fix. Malloc isn't cooperating.) + +=============================================================================== + +Section 7. ACKNOWLEDGEMENTS + + Q7.1 How is this FAQ generated ? + Q7.2 What formats are available ? + Q7.3 Contributors + +----------------------------------------------------------------------------- + +Question 7.1. How is this FAQ generated ? + +Date: Fri Dec 6 16:51:31 EST 1996 + +This FAQ is maintained in BFNN (Bizzarre Format with No Name). This +allows me to create ASCII, HTML, and GNU info (postscript coming soon) +from one source file. + +The perl script "bfnnconv.pl" that is available with the linux FAQ is used +to generate the various output files from the BFNN source. + +----------------------------------------------------------------------------- + +Question 7.2. What formats are available ? + +Date: Fri Dec 6 16:51:31 EST 1996 + +You may obtain one of the following formats for this document: + +* ASCII: http://www.users.pfmc.net/~cdp/cptd-faq/cptd-faq.ascii +* BFNN: http://www.users.pfmc.net/~cdp/cptd-faq/cptd-faq.bfnn +* GNU info: http://www.users.pfmc.net/~cdp/cptd-faq/cptd-faq.info +* HTML: http://www.users.pfmc.net/~cdp/cptd-faq/index.html + +----------------------------------------------------------------------------- + +Question 7.3. Contributors + +Date: Sat Dec 7 01:29:29 EST 1996 + +Many people have helped put this list together. Listed in e-mail address +alphabetical order, the following people have contributed to this FAQ: + +* <Benoit.Grange@inria.fr> (Benoit.Grange) +* <D.T.Shield@csc.liv.ac.uk> (Dave Shield) +* <Todd.Aven@BankersTrust.Com> +* <adam@comptech.demon.co.uk> (Adam Goodfellow) +* <andras@is.co.za> (Andras Salamon) +* <barmar@nic.near.net> (Barry Margolin) +* <barr@pop.psu.edu> (David Barr) +* <bj@herbison.com> (B.J. Herbison) +* <bje@cbr.fidonet.org> (Ben Elliston) +* <brad@birch.ims.disa.mil> (Brad Knowles) +* <ckd@kei.com> (Christopher Davis) +* <cdp2582@hertz.njit.edu> (Chris Peckham) +* <cricket@hp.com> (Cricket Liu) +* <cudep@csv.warwick.ac.uk> (Ian 'Vato' Dickinson [ID17]) +* <dillon@best.com> (Matthew Dillon) +* <dparter@cs.wisc.edu> (David Parter) +* <e07@nikhef.nl> (Eric Wassenaar) +* <fitz@think.com> (Tom Fitzgerald) +* <fwp@CC.MsState.Edu> (Frank Peters) +* <gah@cco.caltech.edu> (Glen A. Herrmannsfeldt) +* <glenn@popco.com> (Glenn Fleishman) +* <harvey@indyvax.iupui.edu> (James Harvey) +* <hubert@cac.washington.edu> (Steve Hubert) +* <ivanl@pacific.net.sg> (Ivan Leong) +* <jhawk@panix.com> (John Hawkinson) +* <jmalcolm@uunet.uu.net> (Joseph Malcolm) +* <jprovo@augustus.ultra.net> (Joe Provo) +* <kevin@cfc.com> (Kevin Darcy) +* <lamont@abstractsoft.com> (Sean T. Lamont) +* <lavondes@tidtest.total.fr> (Michel Lavondes) +* <mark@ucsalf.ac.uk> (Mark Powell) +* <marka@syd.dms.CSIRO.AU> (Mark Andrews) +* <mathias@unicorn.swi.com.sg> (Mathias Koerber) +* <mjo@iao.ford.com> (Mike O'Connor) +* <nick@flapjack.ieunet.ie> (Nick Hilliard) +* <oppedahl@popserver.panix.com> (Carl Oppedahl) +* <patrick@oes.amdahl.com> (Patrick J. Horgan) +* <paul@software.com> (Paul Wren) +* <pb@fasterix.frmug.fr.net> (Pierre Beyssac) +* <ph10@cus.cam.ac.uk> (Philip Hazel) +* <phil@netpart.com> (Phil Trubey) +* <rocky@panix.com> (R. Bernstein) +* <rv@seins.Informatik.Uni-Dortmund.DE> (Ruediger Volk) +* <shields@tembel.org> (Michael Shields) +* <tanner@george.arc.nasa.gov> (Rob Tanner) +* <vixie@vix.com> (Paul A Vixie) +* <wag@swl.msd.ray.com> (William Gianopoulos {84718) +* <whg@inel.gov> (Bill Gray) +* <wolf@pasteur.fr> (Christophe Wolfhugel) Thank you ! |
