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diff --git a/contrib/bind9/doc/draft/draft-ietf-dnsext-dhcid-rr-08.txt b/contrib/bind9/doc/draft/draft-ietf-dnsext-dhcid-rr-08.txt deleted file mode 100644 index 0977661..0000000 --- a/contrib/bind9/doc/draft/draft-ietf-dnsext-dhcid-rr-08.txt +++ /dev/null @@ -1,561 +0,0 @@ - - -DNSEXT M. Stapp -Internet-Draft Cisco Systems, Inc. -Expires: January 14, 2005 T. Lemon - A. Gustafsson - Nominum, Inc. - July 16, 2004 - - - A DNS RR for Encoding DHCP Information (DHCID RR) - <draft-ietf-dnsext-dhcid-rr-08.txt> - -Status of this Memo - - This document is an Internet-Draft and is subject to all provisions - of section 3 of RFC 3667. By submitting this Internet-Draft, each - author represents that any applicable patent or other IPR claims of - which he or she is aware have been or will be disclosed, and any of - which he or she become aware will be disclosed, in accordance with - RFC 3668. - - Internet-Drafts are working documents of the Internet Engineering - Task Force (IETF), its areas, and its working groups. Note that - other groups may also distribute working documents as - Internet-Drafts. - - Internet-Drafts are draft documents valid for a maximum of six months - and may be updated, replaced, or obsoleted by other documents at any - time. It is inappropriate to use Internet-Drafts as reference - material or to cite them other than as "work in progress." - - The list of current Internet-Drafts can be accessed at http:// - www.ietf.org/ietf/1id-abstracts.txt. - - The list of Internet-Draft Shadow Directories can be accessed at - http://www.ietf.org/shadow.html. - - This Internet-Draft will expire on January 14, 2005. - -Copyright Notice - - Copyright (C) The Internet Society (2004). All Rights Reserved. - -Abstract - - It is possible for multiple DHCP clients to attempt to update the - same DNS FQDN as they obtain DHCP leases. Whether the DHCP server or - the clients themselves perform the DNS updates, conflicts can arise. - To resolve such conflicts, "Resolution of DNS Name Conflicts" [1] - proposes storing client identifiers in the DNS to unambiguously - - - -Stapp, et al. Expires January 14, 2005 [Page 1] - -Internet-Draft The DHCID RR July 2004 - - - associate domain names with the DHCP clients to which they refer. - This memo defines a distinct RR type for this purpose for use by DHCP - clients and servers, the "DHCID" RR. - -Table of Contents - - 1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 3. The DHCID RR . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 3.1 DHCID RDATA format . . . . . . . . . . . . . . . . . . . . 4 - 3.2 DHCID Presentation Format . . . . . . . . . . . . . . . . 4 - 3.3 The DHCID RR Type Codes . . . . . . . . . . . . . . . . . 4 - 3.4 Computation of the RDATA . . . . . . . . . . . . . . . . . 4 - 3.5 Examples . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 3.5.1 Example 1 . . . . . . . . . . . . . . . . . . . . . . 6 - 3.5.2 Example 2 . . . . . . . . . . . . . . . . . . . . . . 6 - 4. Use of the DHCID RR . . . . . . . . . . . . . . . . . . . . . 6 - 5. Updater Behavior . . . . . . . . . . . . . . . . . . . . . . . 6 - 6. Security Considerations . . . . . . . . . . . . . . . . . . . 7 - 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 - 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 - 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 9.1 Normative References . . . . . . . . . . . . . . . . . . . . 8 - 9.2 Informative References . . . . . . . . . . . . . . . . . . . 8 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 9 - Intellectual Property and Copyright Statements . . . . . . . . 10 - - - - - - - - - - - - - - - - - - - - - - - - - -Stapp, et al. Expires January 14, 2005 [Page 2] - -Internet-Draft The DHCID RR July 2004 - - -1. Terminology - - The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", - "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this - document are to be interpreted as described in RFC 2119 [2]. - -2. Introduction - - A set of procedures to allow DHCP [7] clients and servers to - automatically update the DNS (RFC 1034 [3], RFC 1035 [4]) is proposed - in "Resolution of DNS Name Conflicts" [1]. - - Conflicts can arise if multiple DHCP clients wish to use the same DNS - name. To resolve such conflicts, "Resolution of DNS Name Conflicts" - [1] proposes storing client identifiers in the DNS to unambiguously - associate domain names with the DHCP clients using them. In the - interest of clarity, it is preferable for this DHCP information to - use a distinct RR type. This memo defines a distinct RR for this - purpose for use by DHCP clients or servers, the "DHCID" RR. - - In order to avoid exposing potentially sensitive identifying - information, the data stored is the result of a one-way MD5 [5] hash - computation. The hash includes information from the DHCP client's - REQUEST message as well as the domain name itself, so that the data - stored in the DHCID RR will be dependent on both the client - identification used in the DHCP protocol interaction and the domain - name. This means that the DHCID RDATA will vary if a single client - is associated over time with more than one name. This makes it - difficult to 'track' a client as it is associated with various domain - names. - - The MD5 hash algorithm has been shown to be weaker than the SHA-1 - algorithm; it could therefore be argued that SHA-1 is a better - choice. However, SHA-1 is significantly slower than MD5. A - successful attack of MD5's weakness does not reveal the original data - that was used to generate the signature, but rather provides a new - set of input data that will produce the same signature. Because we - are using the MD5 hash to conceal the original data, the fact that an - attacker could produce a different plaintext resulting in the same - MD5 output is not significant concern. - -3. The DHCID RR - - The DHCID RR is defined with mnemonic DHCID and type code [TBD]. The - DHCID RR is only defined in the IN class. DHCID RRs cause no - additional section processing. The DHCID RR is not a singleton type. - - - - - -Stapp, et al. Expires January 14, 2005 [Page 3] - -Internet-Draft The DHCID RR July 2004 - - -3.1 DHCID RDATA format - - The RDATA section of a DHCID RR in transmission contains RDLENGTH - bytes of binary data. The format of this data and its interpretation - by DHCP servers and clients are described below. - - DNS software should consider the RDATA section to be opaque. DHCP - clients or servers use the DHCID RR to associate a DHCP client's - identity with a DNS name, so that multiple DHCP clients and servers - may deterministically perform dynamic DNS updates to the same zone. - From the updater's perspective, the DHCID resource record RDATA - consists of a 16-bit identifier type, in network byte order, followed - by one or more bytes representing the actual identifier: - - < 16 bits > DHCP identifier used - < n bytes > MD5 digest - - -3.2 DHCID Presentation Format - - In DNS master files, the RDATA is represented as a single block in - base 64 encoding identical to that used for representing binary data - in RFC 2535 [8]. The data may be divided up into any number of white - space separated substrings, down to single base 64 digits, which are - concatenated to form the complete RDATA. These substrings can span - lines using the standard parentheses. - -3.3 The DHCID RR Type Codes - - The DHCID RR Type Code specifies what data from the DHCP client's - request was used as input into the hash function. The type codes are - defined in a registry maintained by IANA, as specified in Section 7. - The initial list of assigned values for the type code is: - - 0x0000 = htype, chaddr from a DHCPv4 client's DHCPREQUEST [7]. - 0x0001 = The data portion from a DHCPv4 client's Client Identifier - option [9]. - 0x0002 = The client's DUID (i.e., the data portion of a DHCPv6 - client's Client Identifier option [10] or the DUID field from a - DHCPv4 client's Client Identifier option [12]). - - 0x0003 - 0xfffe = Available to be assigned by IANA. - - 0xffff = RESERVED - -3.4 Computation of the RDATA - - The DHCID RDATA is formed by concatenating the two type bytes with - - - -Stapp, et al. Expires January 14, 2005 [Page 4] - -Internet-Draft The DHCID RR July 2004 - - - some variable-length identifying data. - - < type > < data > - - The RDATA for all type codes other than 0xffff, which is reserved for - future expansion, is formed by concatenating the two type bytes and a - 16-byte MD5 hash value. The input to the hash function is defined to - be: - - data = MD5(< identifier > < FQDN >) - - The FQDN is represented in the buffer in unambiguous canonical form - as described in RFC 2535 [8], section 8.1. The type code and the - identifier are related as specified in Section 3.3: the type code - describes the source of the identifier. - - When the updater is using the client's link-layer address as the - identifier, the first two bytes of the DHCID RDATA MUST be zero. To - generate the rest of the resource record, the updater computes a - one-way hash using the MD5 algorithm across a buffer containing the - client's network hardware type, link-layer address, and the FQDN - data. Specifically, the first byte of the buffer contains the - network hardware type as it appeared in the DHCP 'htype' field of the - client's DHCPREQUEST message. All of the significant bytes of the - chaddr field in the client's DHCPREQUEST message follow, in the same - order in which the bytes appear in the DHCPREQUEST message. The - number of significant bytes in the 'chaddr' field is specified in the - 'hlen' field of the DHCPREQUEST message. The FQDN data, as specified - above, follows. - - When the updater is using the DHCPv4 Client Identifier option sent by - the client in its DHCPREQUEST message, the first two bytes of the - DHCID RR MUST be 0x0001, in network byte order. The rest of the - DHCID RR MUST contain the results of computing an MD5 hash across the - payload of the option, followed by the FQDN. The payload of the - option consists of the bytes of the option following the option code - and length. - - When the updater is using the DHCPv6 DUID sent by the client in its - REQUEST message, the first two bytes of the DHCID RR MUST be 0x0002, - in network byte order. The rest of the DHCID RR MUST contain the - results of computing an MD5 hash across the payload of the option, - followed by the FQDN. The payload of the option consists of the - bytes of the option following the option code and length. - -3.5 Examples - - - - - -Stapp, et al. Expires January 14, 2005 [Page 5] - -Internet-Draft The DHCID RR July 2004 - - -3.5.1 Example 1 - - A DHCP server allocating the IPv4 address 10.0.0.1 to a client with - Ethernet MAC address 01:02:03:04:05:06 using domain name - "client.example.com" uses the client's link-layer address to identify - the client. The DHCID RDATA is composed by setting the two type - bytes to zero, and performing an MD5 hash computation across a buffer - containing the Ethernet MAC type byte, 0x01, the six bytes of MAC - address, and the domain name (represented as specified in Section - 3.4). - - client.example.com. A 10.0.0.1 - client.example.com. DHCID AAAUMru0ZM5OK/PdVAJgZ/HU - - -3.5.2 Example 2 - - A DHCP server allocates the IPv4 address 10.0.12.99 to a client which - included the DHCP client-identifier option data 01:07:08:09:0a:0b:0c - in its DHCP request. The server updates the name "chi.example.com" - on the client's behalf, and uses the DHCP client identifier option - data as input in forming a DHCID RR. The DHCID RDATA is formed by - setting the two type bytes to the value 0x0001, and performing an MD5 - hash computation across a buffer containing the seven bytes from the - client-id option and the FQDN (represented as specified in Section - 3.4). - - chi.example.com. A 10.0.12.99 - chi.example.com. DHCID AAHdd5jiQ3kEjANDm82cbObk\012 - - -4. Use of the DHCID RR - - This RR MUST NOT be used for any purpose other than that detailed in - "Resolution of DNS Name Conflicts" [1]. Although this RR contains - data that is opaque to DNS servers, the data must be consistent - across all entities that update and interpret this record. - Therefore, new data formats may only be defined through actions of - the DHC Working Group, as a result of revising [1]. - -5. Updater Behavior - - The data in the DHCID RR allows updaters to determine whether more - than one DHCP client desires to use a particular FQDN. This allows - site administrators to establish policy about DNS updates. The DHCID - RR does not establish any policy itself. - - Updaters use data from a DHCP client's request and the domain name - - - -Stapp, et al. Expires January 14, 2005 [Page 6] - -Internet-Draft The DHCID RR July 2004 - - - that the client desires to use to compute a client identity hash, and - then compare that hash to the data in any DHCID RRs on the name that - they wish to associate with the client's IP address. If an updater - discovers DHCID RRs whose RDATA does not match the client identity - that they have computed, the updater SHOULD conclude that a different - client is currently associated with the name in question. The - updater SHOULD then proceed according to the site's administrative - policy. That policy might dictate that a different name be selected, - or it might permit the updater to continue. - -6. Security Considerations - - The DHCID record as such does not introduce any new security problems - into the DNS. In order to avoid exposing private information about - DHCP clients to public scrutiny, a one-way hash is used to obscure - all client information. In order to make it difficult to 'track' a - client by examining the names associated with a particular hash - value, the FQDN is included in the hash computation. Thus, the RDATA - is dependent on both the DHCP client identification data and on each - FQDN associated with the client. - - Administrators should be wary of permitting unsecured DNS updates to - zones which are exposed to the global Internet. Both DHCP clients - and servers SHOULD use some form of update authentication (e.g., TSIG - [11]) when performing DNS updates. - -7. IANA Considerations - - IANA is requested to allocate an RR type number for the DHCID record - type. - - This specification defines a new number-space for the 16-bit type - codes associated with the DHCID RR. IANA is requested to establish a - registry of the values for this number-space. - - Three initial values are assigned in Section 3.3, and the value - 0xFFFF is reserved for future use. New DHCID RR type codes are - tentatively assigned after the specification for the associated type - code, published as an Internet Draft, has received expert review by a - designated expert. The final assignment of DHCID RR type codes is - through Standards Action, as defined in RFC 2434 [6]. - -8. Acknowledgements - - Many thanks to Josh Littlefield, Olafur Gudmundsson, Bernie Volz, and - Ralph Droms for their review and suggestions. - - - - - -Stapp, et al. Expires January 14, 2005 [Page 7] - -Internet-Draft The DHCID RR July 2004 - - -9. References - -9.1 Normative References - - [1] Stapp, M. and B. Volz, "Resolution of DNS Name Conflicts Among - DHCP Clients (draft-ietf-dhc-dns-resolution-*)", July 2004. - - [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement - Levels", BCP 14, RFC 2119, March 1997. - - [3] Mockapetris, P., "Domain names - concepts and facilities", STD - 13, RFC 1034, November 1987. - - [4] Mockapetris, P., "Domain names - implementation and - specification", STD 13, RFC 1035, November 1987. - - [5] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321, April - 1992. - - [6] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA - Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. - -9.2 Informative References - - [7] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, - March 1997. - - [8] Eastlake, D., "Domain Name System Security Extensions", RFC - 2535, March 1999. - - [9] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor - Extensions", RFC 2132, March 1997. - - [10] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C. and M. - Carney, "Dynamic Host Configuration Protocol for IPv6 - (DHCPv6)", RFC 3315, July 2003. - - [11] Vixie, P., Gudmundsson, O., Eastlake, D. and B. Wellington, - "Secret Key Transaction Authentication for DNS (TSIG)", RFC - 2845, May 2000. - - [12] Lemon, T. and B. Sommerfeld, "Node-Specific Client Identifiers - for DHCPv4 (draft-ietf-dhc-3315id-for-v4-*)", February 2004. - - - - - - - - -Stapp, et al. Expires January 14, 2005 [Page 8] - -Internet-Draft The DHCID RR July 2004 - - -Authors' Addresses - - Mark Stapp - Cisco Systems, Inc. - 1414 Massachusetts Ave. - Boxborough, MA 01719 - USA - - Phone: 978.936.1535 - EMail: mjs@cisco.com - - - Ted Lemon - Nominum, Inc. - 950 Charter St. - Redwood City, CA 94063 - USA - - EMail: mellon@nominum.com - - - Andreas Gustafsson - Nominum, Inc. - 950 Charter St. - Redwood City, CA 94063 - USA - - EMail: gson@nominum.com - - - - - - - - - - - - - - - - - - - - - - - -Stapp, et al. Expires January 14, 2005 [Page 9] - -Internet-Draft The DHCID RR July 2004 - - -Intellectual Property Statement - - The IETF takes no position regarding the validity or scope of any - Intellectual Property Rights or other rights that might be claimed to - pertain to the implementation or use of the technology described in - this document or the extent to which any license under such rights - might or might not be available; nor does it represent that it has - made any independent effort to identify any such rights. 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Please address the information to the IETF at - ietf-ipr@ietf.org. - - -Disclaimer of Validity - - This document and the information contained herein are provided on an - "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS - OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET - ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, - INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE - INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED - WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. - - -Copyright Statement - - Copyright (C) The Internet Society (2004). This document is subject - to the rights, licenses and restrictions contained in BCP 78, and - except as set forth therein, the authors retain all their rights. - - -Acknowledgment - - Funding for the RFC Editor function is currently provided by the - Internet Society. - - - - -Stapp, et al. Expires January 14, 2005 [Page 10] - - |
