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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 If this copy is more +than a month old it may be out of date.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). + |
