Internet DRAFT - draft-damick-dns-associated-names-record
draft-damick-dns-associated-names-record
Internet Engineering Task Force J. Damick
Internet-Draft Neustar
Intended status: Standards Track August 1, 2012
Expires: February 2, 2013
Associated Names DNS Record
draft-damick-dns-associated-names-record-00
Abstract
This document describes a new resource record for the Domain Name
System (DNS) protocol. The record introduced will allow associated
domain names to be associated with a particular domain name and
retrieved in in a single DNS query.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 2, 2013.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . . 3
2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. AN RDATA Format . . . . . . . . . . . . . . . . . . . . . . 3
3.2. Client Handling . . . . . . . . . . . . . . . . . . . . . . 4
3.3. Publishing . . . . . . . . . . . . . . . . . . . . . . . . 4
3.4. Example Flow . . . . . . . . . . . . . . . . . . . . . . . 4
4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
6.1. Denial of Service . . . . . . . . . . . . . . . . . . . . . 6
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.1. Normative References . . . . . . . . . . . . . . . . . . . 6
7.2. Informative References . . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 7
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1. Introduction
The current mechanism for determining associated domain names for a
particular domain name requires multiple queries with interleaved
asset retrieval. One example of this occurs in rendering HTML pages
where the base domain must be queried and then the HTML will be
retrieved and it will most likely will include references to external
assets, such as scripts and stylesheets, to be delivered from many
other domains. The goal of this record is to allow a list of the
other domains that will referenced later by another process, such as
rendering an HTML page, to be published. By providing the list of
referenced domains, they may utilized by a resolver to pre-cache
results, so that when another process needs the results they will
most likely not incur a network round trip.
1.1. Requirements Language
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 [RFC2119].
2. Overview
The associated names (AN) resource record (RR) contains a list of any
domain names that to be associated with this name.
3. Usage
The type number for the AN RR is 'TBD'.
3.1. AN RDATA Format
RDATA Format for the associated names resource record.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| QTYPE | SERVICE /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /
/ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ ASSOCIATED-NAME ... /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1
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QTYPE: The 2 octet TYPE code as defined in [RFC1035] to use for the
associated-names list.
SERVICE: The character-string as defined in [RFC1035] of a symbolic
name for the desired service, as defined in the IANA On-line
database of service names [IANA-SERVICE-NAMES].
ASSOCIATED-NAME: One or more absolute <domain-name>s as defined in
[RFC1035] which are each terminated by a label of zero length.
3.2. Client Handling
It is RECOMMENDED that clients upon receiving the results of this
type then query for the domain-names listed in the ASSOCIATED-NAME
section. This will allow the client to ensure that the results for
the domain-names will be populated in the cache of a local resolver
or recursive resolver.
3.3. Publishing
In the example of a web site, it is RECOMMENDED that the content
owner upon publishing a new version of their site and/or associated
assets also update [RFC2136] the AN resource record with any added or
removed associated domain names.
3.4. Example Flow
This flow uses the example of a web site again:
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Update (AN RR)
www.example.com
QTYPE: 1 (A RR)
SERVICE: http
+-----------+ ASSOCIATED-NAMES: +-----+
| Web Site | a.uk,b.com,c.com | |
| Publisher |+----------------->| DNS |
| | | |
+-----------+ +-----+
Query (AN RR)
+--------+ www.example.com +-----+
| |+----------------->| |
| Client | Response (AN RR) | DNS |
| |<-----------------+| |
+--------+ QTYPE: 1 +-----+
| SERVICE: http
| AN: a.uk,b.com,c.com
|
|
| Query (A RR)
www.example.com,a.uk,b.com,c.com
+--------+ +-----+
| |+----------------->| |
| Client |+----------------->| DNS |
| |+----------------->| |
| |------------------>| |
+--------+ +-----+
|
|
.. process & render html and scripts ..
|
|
+--------++-----+ Query (A RR)
| |+-----+ a.uk,b.com,c.com
| Client |+-----+ (answer from stub resolver cache)
| | |
| |<-----+
+--------+
Figure 2
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4. Acknowledgements
Thanks to Edward Lewis and the rest of the UltraDNS team for all of
their valuable input.
5. IANA Considerations
This document requests that the IANA Registry for DNS Resource Record
Types assigns type 'TBD' to the AN resource record.
6. Security Considerations
6.1. Denial of Service
The DNS servers themselves will not be effected directly by misuse of
the AN record it is still important to note potential risks to a
client application. It is possible for an attacker to create AN
records of the following types:
o Very large list of domain names
o Duplicate domain names
When dealing with these situations it is important for client
applications to take precautions to prevent abuse of this resource
record.
o Constrain the list of domains to an upper bound, such as: 50
o Filter duplicate domain names
While these are not foolproof methods, it will likely prevent simple
denial of service attacks.
7. References
7.1. Normative References
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
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7.2. Informative References
[I-D.narten-iana-considerations-rfc2434bis]
Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs",
draft-narten-iana-considerations-rfc2434bis-09 (work in
progress), March 2008.
[IANA-SERVICE-NAMES]
IANA, "Service Name and Transport Protocol Port Number
Registry", <http://www.iana.org/assignments/
service-names-port-numbers/
service-names-port-numbers.txt>.
[RFC2136] Vixie, P., Thomson, S., Rekhter, Y., and J. Bound,
"Dynamic Updates in the Domain Name System (DNS UPDATE)",
RFC 2136, April 1997.
[RFC3232] Reynolds, J., "Assigned Numbers: RFC 1700 is Replaced by
an On-line Database", RFC 3232, January 2002.
[RFC6335] Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S.
Cheshire, "Internet Assigned Numbers Authority (IANA)
Procedures for the Management of the Service Name and
Transport Protocol Port Number Registry", BCP 165,
RFC 6335, August 2011.
Author's Address
Jeffrey Damick
Neustar
46000 Center Oak Plaza
Sterling, VA 20166
US
Email: jeffrey.damick@neustar.biz
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