You are here: irt.org | RFCs | RFC6742 [ previous next ]
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) Abstract This 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. Atkinson, et al. Experimental [Page 1]
RFC 6742 ILNP DNS November 2012 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. Table of Contents 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 1. Introduction This document is part of the ILNP document set, which has had extensive review within the IRTF Routing RG. ILNP is one of the recommendations made by the RG Chairs. Separately, various refereed research papers on ILNP have also been published during this decade. So, the ideas contained herein have had much broader review than the IRTF Routing RG. The views in this document were considered controversial by the Routing RG, but the RG reached a consensus that the document still should be published. The Routing RG has had remarkably little consensus on anything, so virtually all Routing RG outputs are considered controversial. Atkinson, et al. Experimental [Page 2]
RFC 6742 ILNP DNS November 2012 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]. Atkinson, et al. Experimental [Page 3]
RFC 6742 ILNP DNS November 2012 1.1. Document Roadmap This document describes defines additional DNS resource records that support ILNP. The ILNP architecture can have more than one engineering instantiation. For example, one can imagine a "clean-slate" engineering design based on the ILNP architecture. In separate documents, we describe two specific engineering instances of ILNP. The term "ILNPv6" refers precisely to an instance of ILNP that is based upon, and backwards compatible with, IPv6. The term "ILNPv4" refers precisely to an instance of ILNP that is based upon, and backwards compatible with, IPv4. Many engineering aspects common to both ILNPv4 and ILNPv6 are described in [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. Atkinson, et al. Experimental [Page 4]
RFC 6742 ILNP DNS November 2012 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. 1.2. Terminology In this document, the term "ILNP-aware" applied to a DNS component (either authoritative server or cache) is used to indicate that the component attempts to include other ILNP RRTypes to the Additional section of a DNS response to increase performance and reduce the number of follow-up queries for other ILNP RRTypes. These other RRsets MAY be added to the Additional section if space permits and only when the QTYPE equals NID, L64, L32, or LP. There is no method for a server to signal that it is ILNP-aware. 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 [RFC2119]. 2. New Resource Records This document specifies several new and closely related DNS data resource records (RRs). These new RR types have the mnemonics "NID", "L32", "L64", and "LP". These RR types are associated with a Fully Qualified Domain Name (FQDN) that is hereafter called the "owner name". These are part of work on the Identifier-Locator Network Protocol (ILNP) [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). 2.1. The NID Resource Record The Node Identifier (NID) DNS resource record (RR) is used hold values for Node Identifiers that will be used for ILNP-capable nodes. NID records are present only for ILNP-capable nodes. This restriction is important; ILNP-capable nodes use the presence of NID records in the DNS to learn that a correspondent node is also ILNP- capable. While erroneous NID 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. Atkinson, et al. Experimental [Page 5]
RFC 6742 ILNP DNS November 2012 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. 2.1.1. NID RDATA Wire Format The RDATA for an NID RR consists of: - a 16-bit Preference field - a 64-bit NodeID field 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Preference | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | NodeID | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2.1.1.1. The Preference Field The <Preference> field contains a 16-bit unsigned integer in network byte order that indicates the owner name's relative preference for this NID record among other NID records associated with this owner name. Lower Preference values are preferred over higher Preference values. 2.1.1.2. The NodeID Field The NodeID field is an unsigned 64-bit value in network byte order. It complies with the syntactic rules of IPv6 interface identifiers [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. Atkinson, et al. Experimental [Page 6]
RFC 6742 ILNP DNS November 2012 2.1.2. NID RR Presentation Format The presentation of the format of the RDATA portion is as follows: - The Preference field MUST be represented as a 16-bit unsigned decimal integer. - The NodeID field MUST be represented using the same syntax (i.e., groups of 4 hexadecimal digits, with each group separated by a colon) that is already used for DNS AAAA records (and also used for IPv6 interface IDs). - The NodeID value MUST NOT be in the 'compressed' format (e.g., using "::") that is defined in 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. 2.1.3. NID RR Examples An NID record has the following logical components: <owner-name> IN NID <Preference> <NodeID> In the above, <owner-name> is the owner name string, <Preference> is an unsigned 16-bit value, and <NodeID> is an unsigned 64-bit value. host1.example.com. IN NID 10 0014:4fff:ff20:ee64 host1.example.com. IN NID 20 0015:5fff:ff21:ee65 host2.example.com. IN NID 10 0016:6fff:ff22:ee66 As NodeID values use the same syntax as IPv6 interface identifiers, when displayed for human readership, the NodeID values are presented in the same hexadecimal format as IPv6 interface identifiers. This is shown in the example above. 2.1.4. Additional Section Processing To improve performance, ILNP-aware DNS servers and DNS resolvers MAY attempt to return all L32, L64, and LP records for the same owner name of the NID RRset in the Additional section of the response, if space permits. 2.2. The L32 Resource Record An L32 DNS RR is used to hold 32-bit Locator values for ILNPv4-capable nodes. Atkinson, et al. Experimental [Page 7]
RFC 6742 ILNP DNS November 2012 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. 2.2.1. L32 RDATA Wire Format The RDATA for an L32 RR consists of: - a 16-bit Preference field - a 32-bit Locator32 field 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Preference | Locator32 (16 MSBs) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Locator32 (16 LSBs) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ MSB = most significant bit LSB = least significant bit Atkinson, et al. Experimental [Page 8]
RFC 6742 ILNP DNS November 2012 2.2.1.1. The Preference Field The <Preference> field is an unsigned 16-bit field in network byte order that indicates the owner name's relative preference for this L32 record among other L32 records associated with this owner name. Lower Preference values are preferred over higher Preference values. 2.2.1.2. The Locator32 Field The <Locator32> field is an unsigned 32-bit integer in network byte order that is identical on-the-wire to the ADDRESS field of the existing DNS A record. 2.2.2. L32 RR Presentation Format The presentation of the format of the RDATA portion is as follows: - The Preference field MUST be represented as a 16-bit unsigned decimal integer. - The Locator32 field MUST be represented using the same syntax used for existing DNS A records (i.e., 4 decimal numbers separated by periods without any embedded spaces). 2.2.3. L32 RR Examples An L32 record has the following logical components: <owner-name> IN L32 <Preference> <Locator32> In the above <owner-name> is the owner name string, <Preference> is an unsigned 16-bit value, and <Locator32> is an unsigned 32-bit value. host1.example.com. IN L32 10 10.1.02.0 host1.example.com. IN L32 20 10.1.04.0 host2.example.com. IN L32 10 10.1.08.0 As L32 values have the same syntax and semantics as IPv4 routing prefixes, when displayed for human readership, the values are presented in the same dotted-decimal format as IPv4 addresses. An example of this syntax is shown above. In the example above, the owner name is from an FQDN for an individual host. host1.example.com has two L32 values, so host1.example.com is multihomed. Atkinson, et al. Experimental [Page 9]
RFC 6742 ILNP DNS November 2012 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. 2.2.4. Additional Section Processing To improve performance, ILNP-aware DNS servers and DNS resolvers MAY attempt to return all NID, L64, and LP records for the same owner name of the L32 RRset in the Additional section of the response, if space permits. 2.3. The L64 Resource Record The L64 resource record (RR) is used to hold unsigned 64-bit Locator values for ILNPv6-capable nodes. L64 records are present only for ILNPv6-capable nodes. This restriction is important; ILNP-capable nodes use the presence of L64 records in the DNS to learn that a correspondent node is also ILNPv6-capable. While erroneous L64 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 L64 values at a given time. An ILNPv6-capable host SHOULD have at least 1 Locator (i.e., L64 or LP) DNS resource record while it is connected to the Internet. An ILNPv6-capable multihomed host normally will have multiple Locator values while multihomed. An IP host that is NOT ILNPv6-capable MUST NOT have an L64 or LP record in its DNS entries. A node that is not currently connected to the Internet might not have any L64 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 L64 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 L64 RR type is 106. Atkinson, et al. Experimental [Page 10]
RFC 6742 ILNP DNS November 2012 The L64 RR is class independent. The L64 RR has no special TTL requirements. 2.3.1. The L64 RDATA Wire Format The RDATA for an L64 RR consists of: - a 16-bit Preference field - a 64-bit Locator64 field 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Preference | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Locator64 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2.3.1.1. The Preference Field The <Preference> field is an unsigned 16-bit integer in network byte order that indicates the owner name's relative preference for this L64 record among other L64 records associated with this owner name. Lower Preference values are preferred over higher Preference values. 2.3.1.2. The Locator64 Field The <Locator64> field is an unsigned 64-bit integer in network byte order that has the same syntax and semantics as a 64-bit IPv6 routing prefix. 2.3.2. L64 RR Presentation Format The presentation of the format of the RDATA portion is as follows: - The Preference field MUST be represented as a 16-bit unsigned decimal integer. - The Locator64 field MUST be represented using the same syntax used for AAAA records (i.e., groups of 4 hexadecimal digits separated by colons). However, the 'compressed' display format (e.g., using "::") that is specified in 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. Atkinson, et al. Experimental [Page 11]
RFC 6742 ILNP DNS November 2012 2.3.3. L64 RR Examples An L64 record has the following logical components: <owner-name> IN L64 <Preference> <Locator64> In the above, <owner-name> is the owner name string, <Preference> is an unsigned 16-bit value, while <Locator64> is an unsigned 64-bit value. host1.example.com. IN L64 10 2001:0DB8:1140:1000 host1.example.com. IN L64 20 2001:0DB8:2140:2000 host2.example.com. IN L64 10 2001:0DB8:4140:4000 As L64 values have the same syntax and semantics as IPv6 routing prefixes, when displayed for human readership, the values might conveniently be presented in hexadecimal format, as above. In the example above, the owner name is from an FQDN for an individual host. host1.example.com has two L64 values, so it will be multihomed. Another example is when the owner name is that learned from an LP record (see below for details of LP records). l64-subnet1.example.com. IN L64 10 2001:0DB8:1140:1000 l64-subnet2.example.com. IN L64 20 2001:0DB8:2140:2000 l64-subnet3.example.com. IN L64 30 2001:0DB8:4140:4000 Here, the owner name is for a subnetwork rather than an individual node. 2.3.4. Additional Section Processing To improve performance, ILNP-aware DNS servers and DNS resolvers MAY attempt to return all NID, L32, and LP records for the same owner name of the L64 RRset in the Additional section of the response, if space permits. 2.4. The LP Resource Record The LP DNS resource record (RR) is used to hold the name of a subnetwork for ILNP. The name is an FQDN which can then be used to look up L32 or L64 records. LP is, effectively, a Locator Pointer to L32 and/or L64 records. Atkinson, et al. Experimental [Page 12]
RFC 6742 ILNP DNS November 2012 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. 2.4.1. LP RDATA Wire Format The RDATA for an LP RR consists of: - an unsigned 16-bit Preference field - a variable-length FQDN field 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Preference | / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / / / / FQDN / / / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2.4.1.1. The Preference Field The <Preference> field contains an unsigned 16-bit integer in network byte order that indicates the owner name's relative preference for this LP record among other LP records associated with this owner name. Lower Preference values are preferred over higher Preference values. Atkinson, et al. Experimental [Page 13]
RFC 6742 ILNP DNS November 2012 2.4.1.2. The FQDN Field The variable-length FQDN field contains the DNS target name that is used to reference L32 and/or L64 records. This field MUST NOT have the same value as the owner name of the LP RR instance. A sender MUST NOT use DNS name compression on the FQDN field when transmitting an LP RR. 2.4.2. LP RR Presentation Format The presentation of the format of the RDATA portion is as follows: - The Preference field MUST be represented as a 16-bit unsigned decimal integer. - The FQDN field MUST be represented as a domain name. 2.4.3. LP RR Examples An LP record has the following logical components: <owner-name> IN LP <Preference> <FQDN> In the above, <owner-name> is the owner name string, <Preference> is an unsigned 16-bit value, while <FQDN> is the domain name which should be resolved further. host1.example.com. IN LP 10 l64-subnet1.example.com. host1.example.com. IN LP 10 l64-subnet2.example.com. host1.example.com. IN LP 20 l32-subnet1.example.com. In the example above, host1.example.com is multihomed on three subnets. Resolving the FQDNs return in the LP records would allow the actual subnet prefixes to be resolved, e.g., as in the examples for the L32 and L64 RR descriptions, above. This level of indirection allows the same L32 and/or L64 records to be used by many hosts in the same subnetwork, easing management of the ILNP network and potentially reducing the number of DNS Update transactions, especially when that network is mobile [RAB09] or multihomed [ABH09a]. 2.4.4. Additional Section Processing To improve performance, ILNP-aware DNS servers and DNS resolvers MAY attempt to return all L32 and L64 records for the same owner name of the LP RRset in the Additional section of the response, if space permits. Atkinson, et al. Experimental [Page 14]
RFC 6742 ILNP DNS November 2012 3. Deployment Example Given a domain name, one can use the Domain Name System (DNS) to discover the set of NID records, the set of L32 records, the set of L64 records, and the set of LP records that are associated with that DNS owner name. For example: host1.example.com. IN NID 10 0014:4fff:ff20:ee64 host1.example.com. IN L64 10 2001:0DB8:1140:1000 would be the minimum requirement for an ILNPv6 node that has owner name host1.example.com and is connected to the Internet at the subnetwork having routing prefix 2001:0DB8:1140:1000. If that host were multihomed on two different IPv6 subnets: host1.example.com. IN NID 10 0014:4fff:ff20:ee64 host1.example.com. IN L64 10 2001:0DB8:1140:1000 host1.example.com. IN L64 20 2001:0DB8:2140:2000 would indicate the Identifier and two subnets that host1.example.com is attached to, along with the relative preference that a client would use in selecting the Locator value for use in initiating communication. If host1.example.com were part of a mobile network, a DNS query might return: host1.example.com. IN NID 10 0014:4fff:ff20:ee64 host1.example.com. IN LP 10 mobile-net1.example.com. and then a DNS query to find the current Locator value(s) for the node named by the LP record: mobile-net1.example.com. IN L64 2001:0DB8:8140:8000 3.1. Use of ILNP Records As these DNS records are only used with the Identifier-Locator Network Protocol (ILNP), these records MUST NOT be present for a node that does not support ILNP. This lookup process is considered to be in the "forward" direction. The Preference fields associated with the NID, L32, L64, and LP records are used to indicate the owner name's preference for others to use one particular NID, L32, L64, or LP record, rather than use Atkinson, et al. Experimental [Page 15]
RFC 6742 ILNP DNS November 2012 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]. 3.2. Additional Section Processing For all the records above, Additional Section Processing MAY be used. This is intended to improve performance for both the DNS client and the DNS server. For example, a node sending DNS query for an NID owner name, such as host1.example.com, would benefit from receiving all ILNP DNS records related to that owner name being returned, as it is quite likely that the client will need that information to initiate an ILNP session. Atkinson, et al. Experimental [Page 16]
RFC 6742 ILNP DNS November 2012 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. 4. Security Considerations These new DNS resource record types do not create any new vulnerabilities in the Domain Name System. Existing mechanisms for DNS Security can be used unchanged with these record types [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. 5. IANA Considerations IANA has allocated each of the following DNS resource records (described above in 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 6. References 6.1. Normative References [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. Atkinson, et al. Experimental [Page 17]
RFC 6742 ILNP DNS November 2012 [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. 6.2. Informative References [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> Atkinson, et al. Experimental [Page 18]
RFC 6742 ILNP DNS November 2012 [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. Atkinson, et al. Experimental [Page 19]
RFC 6742 ILNP DNS November 2012 7. Acknowledgements Steve Blake, Stephane Bortzmeyer, Mohamed Boucadair, Noel Chiappa, Wes George, Steve Hailes, Joel Halpern, Mark Handley, Volker Hilt, Paul Jakma, Dae-Young Kim, Tony Li, Yakov Rehkter, Bruce Simpson, Robin Whittle, and John Wroclawski (in alphabetical order) provided review and feedback on earlier versions of this document. Steve Blake provided an especially thorough review of an early version of the entire ILNP document set, which was extremely helpful. We also wish to thank the anonymous reviewers of the various ILNP papers for their feedback. Roy Arends provided expert guidance on technical and procedural aspects of DNS issues, for which the authors are greatly obliged. Authors' Addresses RJ Atkinson Consultant San Jose, CA 95125 USA EMail: rja.lists@gmail.com SN Bhatti School of Computer Science University of St Andrews North Haugh, St Andrews Fife, Scotland KY16 9SX, UK EMail: saleem@cs.st-andrews.ac.uk Scott Rose US National Institute for Standards & Technology 100 Bureau Drive Gaithersburg, MD 20899 USA EMail: scottr.nist@gmail.com Atkinson, et al. Experimental [Page 20]