Internet Research Task Force (IRTF) RJ Atkinson Request for Comments: 6742 Consultant Category: Experimental SN Bhatti ISSN: 2070-1721 U. St Andrews S. Rose US NIST November 2012 DNS Resource Records for the Identifier-Locator Network Protocol (ILNP)
AbstractThis note describes additional optional resource records for use with the Domain Name System (DNS). These optional resource records are for use with the Identifier-Locator Network Protocol (ILNP). This document is a product of the IRTF Routing Research Group. Status of This Memo This document is not an Internet Standards Track specification; it is published for examination, experimental implementation, and evaluation. This document defines an Experimental Protocol for the Internet community. This document is a product of the Internet Research Task Force (IRTF). The IRTF publishes the results of Internet-related research and development activities. These results might not be suitable for deployment. This RFC represents the individual opinion(s) of one or more members of the Routing Research Group of the Internet Research Task Force (IRTF). Documents approved for publication by the IRSG are not a candidate for any level of Internet Standard; see Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6742.
Copyright Notice Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. This document may not be modified, and derivative works of it may not be created, except to format it for publication as an RFC or to translate it into languages other than English. 1. Introduction ....................................................2 1.1. Document Roadmap ...........................................4 1.2. Terminology ................................................5 2. New Resource Records ............................................5 2.1. The NID Resource Record ....................................5 2.2. The L32 Resource Record ....................................7 2.3. The L64 Resource Record ...................................10 2.4. The LP Resource Record ....................................12 3. Deployment Example .............................................15 3.1. Use of ILNP Records .......................................15 3.2. Additional Section Processing .............................16 4. Security Considerations ........................................17 5. IANA Considerations ............................................17 6. References .....................................................17 6.1. Normative References ......................................17 6.2. Informative References ....................................18 7. Acknowledgements ...............................................20
At present, the Internet research and development community is exploring various approaches to evolving the Internet Architecture to solve a variety of issues including, but not limited to, scalability of inter-domain routing [RFC4984]. A wide range of other issues (e.g., site multihoming, node multihoming, site/subnet mobility, node mobility) are also active concerns at present. Several different classes of evolution are being considered by the Internet research and development community. One class is often called "Map and Encapsulate", where traffic would be mapped and then tunnelled through the inter-domain core of the Internet. Another class being considered is sometimes known as "Identifier/Locator Split". This document relates to a proposal that is in the latter class of evolutionary approaches. The Identifier-Locator Network Protocol (ILNP) was developed to explore a possible evolutionary direction for the Internet Architecture. A description of the ILNP architecture is available in a separate document [RFC6740]. Implementation and engineering details are largely isolated into a second document [RFC6741]. The Domain Name System (DNS) is the standard way that Internet nodes locate information about addresses, mail exchangers, and other data relating to remote Internet nodes [RFC1034] [RFC1035]. More recently, the IETF has defined standards-track security extensions to the DNS [RFC4033]. These security extensions can be used to authenticate signed DNS data records and can be used to store signed public keys in the DNS. Further, the IETF has defined a standards-track approach to enable secure dynamic update of DNS records over the network [RFC3007]. This document defines several new optional data resource records. This note specifies the syntax and other items required for independent implementations of these DNS resource records. The reader is assumed to be familiar with the basics of DNS, including familiarity with [RFC1034] [RFC1035]. The concept of using DNS for rendezvous with mobile nodes or mobile networks has been proposed earlier, more than once, independently, by several other researchers; for example, please see [SB00], [SBK01], and [PHG02].
RFC6741]. A full engineering specification for either ILNPv6 or ILNPv4 is beyond the scope of this document. Readers are referred to other related ILNP documents for details not described here: a) [RFC6740] is the main architectural description of ILNP, including the concept of operations. b) [RFC6741] describes engineering and implementation considerations that are common to both ILNPv4 and ILNPv6. c) [RFC6743] defines a new ICMPv6 Locator Update message used by an ILNP node to inform its correspondent nodes of any changes to its set of valid Locators. d) [RFC6744] defines a new IPv6 Nonce Destination Option used by ILNPv6 nodes (1) to indicate to ILNP correspondent nodes (by inclusion within the initial packets of an ILNP session) that the node is operating in the ILNP mode and (2) to prevent off-path attacks against ILNP ICMP messages. This Nonce is used, for example, with all ILNP ICMPv6 Locator Update messages that are exchanged among ILNP correspondent nodes. e) [RFC6745] defines a new ICMPv4 Locator Update message used by an ILNP node to inform its correspondent nodes of any changes to its set of valid Locators. f) [RFC6746] defines a new IPv4 Nonce Option used by ILNPv4 nodes to carry a security nonce to prevent off-path attacks against ILNP ICMP messages and also defines a new IPv4 Identifier Option used by ILNPv4 nodes.
g) [RFC6747] describes extensions to Address Resolution Protocol (ARP) for use with ILNPv4. h) [RFC6748] describes optional engineering and deployment functions for ILNP. These are not required for the operation or use of ILNP and are provided as additional options. RFC2119]. RFC6740]. For clarity, throughout this section of this document, the "RDATA" subsections specify the on-the-wire format for these records, while the "Presentation Format" subsections specify the human-readable format used in a DNS configuration file (i.e., "master file" as defined by RFC 1035, Section 5.1).
A given owner name may have zero or more NID records at a given time. In normal operation, nodes that support the Identifier-Locator Network Protocol (ILNP) will have at least one valid NID record. The type value for the NID RR type is 104. The NID RR is class independent. The NID RR has no special Time to Live (TTL) requirements. RFC4291], Section 2.5.1, but has slightly different semantics. Unlike IPv6 interface identifiers, which are bound to a specific *interface* of a specific node, NodeID values are bound to a specific *node*, and they MAY be used with *any interface* of that node.
RFC 4291, Section 2.2 (2). This restriction exists to avoid confusion with 128-bit IPv6 addresses, because the NID is a 64-bit field.
L32 records are present only for ILNPv4-capable nodes. This restriction is important; ILNP-capable nodes use the presence of L32 records in the DNS to learn that a correspondent node is also ILNPv4-capable. While erroneous L32 records in the DNS for a node that is not ILNP-capable would not prevent communication, such erroneous DNS records could increase the delay at the start of an IP session. A given owner name might have zero or more L32 values at a given time. An ILNPv4-capable host SHOULD have at least 1 Locator (i.e., L32 or LP) DNS resource record while it is connected to the Internet. An ILNPv4-capable multihomed host normally will have multiple Locator values while multihomed. An IP host that is NOT ILNPv4-capable MUST NOT have an L32 or LP record in its DNS entries. A node that is not currently connected to the Internet might not have any L32 values in the DNS associated with its owner name. A DNS owner name that is naming a subnetwork, rather than naming a host, MAY have an L32 record as a wild-card entry, thereby applying to entries under that DNS owner name. This deployment scenario probably is most common if the named subnetwork is, was, or might become, mobile. The type value for the L32 RR type is 105. The L32 RR is class independent. The L32 RR has no special TTL requirements.
Another example is when the owner name is that learned from an LP record (see below for details of LP records). l32-subnet1.example.com. IN L32 10 10.1.02.0 l32-subnet2.example.com. IN L32 20 10.1.04.0 l32-subnet3.example.com. IN L32 30 10.1.08.0 In this example above, the owner name is for a subnetwork rather than an individual node.
The L64 RR is class independent. The L64 RR has no special TTL requirements. RFC 4291, Section 2.2 (2), MUST NOT be used. This is done to avoid confusion with a 128-bit IPv6 address, since the Locator64 is a 64-bit value, while the IPv6 address is a 128-bit value.
As described in [RFC6740], the LP RR provides one level of indirection within the DNS in naming a Locator value. This is useful in several deployment scenarios, such as for a multihomed site where the multihoming is handled entirely by the site's border routers (e.g., via Locator rewriting) or in some mobile network deployment scenarios [RFC6748]. LP records MUST NOT be present for owner name values that are not ILNP-capable nodes. This restriction is important; ILNP-capable nodes use the presence of LP records in the DNS to infer that a correspondent node is also ILNP-capable. While erroneous LP records in the DNS for an owner name would not prevent communication, presence of such erroneous DNS records could increase the delay at the start of an IP session. The type value for the LP RR type is 107. The LP RR is class independent. The LP RR has no special TTL requirements.
another NID, L32, L64, or LP record also associated with that owner name. Lower Preference field values are preferred over higher Preference field values. It is possible that a DNS stub resolver querying for one of these record types will not receive all NID, L32, L64, and LP RR's in a single response. Credible anecdotal reports indicate at least one DNS recursive cache implementation actively drops all Additional Data records that were not expected by that DNS recursive cache. So even if the authoritative DNS server includes all the relevant records in the Additional Data section of the DNS response, the querying DNS stub resolver might not receive all of those Additional Data records. DNS resolvers also might purge some ILNP RRsets before others, for example, if NID RRsets have a longer DNS TTL value than Locator- related (e.g., LP, L32, L64) RRsets. So a DNS stub resolver sending queries to a DNS resolver cannot be certain if they have obtained all available RRtypes for a given owner name. Therefore, the DNS stub resolver SHOULD send follow-up DNS queries for RRTYPE values that were missing and are desired, to ensure that the DNS stub resolver receives all the necessary information. Note nodes likely either to be mobile or to be multihomed normally will have very low DNS TTL values for L32 and L64 records, as those values might change frequently. However, the DNS TTL values for NID and LP records normally will be higher, as those values are not normally impacted by node location changes. Previous trace-driven DNS simulations from MIT [JSBM02] and more recent experimental validation of operational DNS from U. of St Andrews [BA11] both indicate deployment and use of very short DNS TTL values within 'stub' or 'leaf' DNS domains is not problematic. An ILNP node MAY use any NID value associated with its DNS owner name with any or all Locator (L32 or L64) values also associated with its DNS owner name. Existing DNS servers that do not explicitly support the new DNS RRs defined in this specification are expected to follow existing standards for handling unknown DNS RRs [RFC3597].
However, this is not always the case: a DNS query for L64 for a particular owner name might be made because the DNS TTL for a previously resolved L64 RR has expired, while the NID RR for that same owner name has a DNS TTL that has not expired. RFC4033] [RFC3007]. As of this writing, the DNS Security mechanisms are believed to be widely implemented in currently available DNS servers and DNS clients. Deployment of DNS Security appears to be growing rapidly. In situations where authentication of DNS data is a concern, the DNS Security extensions SHOULD be used [RFC4033]. If these DNS records are updated dynamically over the network, then the Secure Dynamic DNS Update [RFC3007] mechanism SHOULD be used to secure such transactions. Section 2) a Data RRTYPE value according to the procedures of Sections 3.1 and 3.1.1 of [RFC6195]. Type Value ---- ----- NID 104 L32 105 L64 106 LP 107 [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", STD 13, RFC 1034, November 1987. [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.
[RFC3007] Wellington, B., "Secure Domain Name System (DNS) Dynamic Update", RFC 3007, November 2000. [RFC3597] Gustafsson, A., "Handling of Unknown DNS Resource Record (RR) Types", RFC 3597, September 2003. [RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "DNS Security Introduction and Requirements", RFC 4033, March 2005. [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture", RFC 4291, February 2006. [RFC6195] Eastlake 3rd, D., "Domain Name System (DNS) IANA Considerations", BCP 42, RFC 6195, March 2011. [RFC6740] Atkinson, R. and S. Bhatti, "Identifier-Locator Network Protocol (ILNP) Architectural Description", RFC 6740, November 2012. [RFC6741] Atkinson, R. and S. Bhatti, "Identifier-Locator Network Protocol (ILNP) Engineering and Implementation Considerations", RFC 6741, November 2012. [ABH09a] Atkinson, R., Bhatti, S. and S. Hailes, "Site-Controlled Secure Multi-Homing and Traffic Engineering For IP", Proceedings of IEEE Military Communications Conference, IEEE, Boston, MA, USA, October 2009. [BA11] Bhatti, S. and R. Atkinson, "Reducing DNS Caching", Proceedings of IEEE Global Internet Symposium (GI2011), Shanghai, P.R. China. 15 April 2011. <http://dx.doi.org/10.1109/INFCOMW.2011.5928919> [JSBM02] Jung, J., Sit, E., Balakrishnan, H., and R. Morris, "DNS performance and the effectiveness of caching", IEEE/ACM Trans. Netw. 10(5) (October 2002), pp 589-603. <http://dx.doi.org/10.1109/TNET.2002.803905> [PHG02] Pappas, A., Hailes, S. and R. Giaffreda, "Mobile Host Location Tracking through DNS", IEEE London Communications Symposium, London, England, UK, September 2002. <http://www.ee.ucl.ac.uk/lcs/previous/LCS2002/LCS072.pdf>
[RAB09] Rehunathan, D., Atkinson, R. and S. Bhatti, "Enabling Mobile Networks Through Secure Naming", Proceedings of IEEE Military Communications Conference (MILCOM), IEEE, Boston, MA, USA, October 2009. [SB00] Snoeren, A. and H. Balakrishnan, "An End-To-End Approach To Host Mobility", Proceedings of 6th Conference on Mobile Computing and Networking (MobiCom), ACM, Boston, MA, USA, August 2000. [SBK01] Snoeren, A., Balakrishnan, H., and M. Frans Kaashoek, "Reconsidering Internet Mobility", Proceedings of 8th Workshop on Hot Topics in Operating Systems (HotOS), IEEE Computer Society, Elmau, Germany, May 2001. [RFC4984] Meyer, D., Ed., Zhang, L., Ed., and K. Fall, Ed., "Report from the IAB Workshop on Routing and Addressing", RFC 4984, September 2007. [RFC6743] Atkinson, R. and S. Bhatti, "ICMPv6 Locator Update Message", RFC 6743, November 2012. [RFC6744] Atkinson, R. and S. Bhatti, "IPv6 Nonce Destination Option for the Identifier-Locator Network Protocol for IPv6 (ILNPv6)", RFC 6744, November 2012. [RFC6745] Atkinson, R. and S. Bhatti, "ICMP Locator Update Message for the Identifier-Locator Network Protocol for IPv4 (ILNPv4)", RFC 6745, November 2012. [RFC6746] Atkinson, R. and S.Bhatti, "IPv4 Options for the Identifier-Locator Network Protocol (ILNP)", RFC 6746, November 2012. [RFC6747] Atkinson, R. and S. Bhatti, "Address Resolution Protocol (ARP) Extension for the Identifier-Locator Network Protocol for IPv4 (ILNPv4)", RFC 6747, November 2012. [RFC6748] Atkinson, R. and S. Bhatti, "Optional Advanced Deployment Scenarios for the Identifier-Locator Network Protocol (ILNP)", RFC 6748, November 2012.