Unique Local IPv6 Unicast Addresses
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From: The IESG <firstname.lastname@example.org> To: IETF-Announce <email@example.com> Cc: Internet Architecture Board <firstname.lastname@example.org>, RFC Editor <email@example.com> Subject: Protocol Action: 'Unique Local IPv6 Unicast Addresses' to Proposed Standard The IESG has approved the following document: - 'Unique Local IPv6 Unicast Addresses ' <draft-ietf-ipv6-unique-local-addr-10.txt> as a Proposed Standard This document is the product of the IP Version 6 Working Group. The IESG contact persons are Margaret Wasserman and Mark Townsley. A URL of this Internet-Draft is: http://www.ietf.org/internet-drafts/draft-ietf-ipv6-unique-local-addr-10.txt
Technical Summary This document defines an IPv6 unicast address format, called Unique Local IPv6 Unicast Addresses, that is globally unique and is intended for local communications.Â This document defines thes subset of Unique Local Addresses that can be allocated locally by the site. These addresses are intended to be the replacement for the Site-Local IPv6 addresses that are being deprecated.Â The ULA addresses offer a similar facility without the drawbacks associated with Site-Local unicast addresses. Working Group Summary The IPv6 working group has done extensive review of this document and this document reflects the consensus of the group. Protocol Quality This document has been reviewed by members of the firstname.lastname@example.org mailing list and by the working group chairs. This document has been reviewed for the IESG by Margaret Wasserman. RFC Editor Note OLD: 4.4 DNS Issues At the present time AAAA and PTR records for locally assigned local IPv6 addresses are not recommended to be installed in the global DNS. The operational issues relating to this are beyond the scope of this document. For background on this recommendation, the concern about adding AAAA and PTR records to the global DNS for locally assigned Local IPv6 addresses stems from the lack of complete assurance that the prefixes are unique. There is a small possibility that the same PTR record might be registered by two different organizations. Due to this concern, adding AAAA records is thought to be unwise because matching PTR records can not be registered NEW: 4.4 DNS Issues At the present time AAAA and PTR records for locally assigned local IPv6 addresses are not recommended to be installed in the global DNS. For background on this recommendation, one of the concerns about adding AAAA and PTR records to the global DNS for locally assigned Local IPv6 addresses stems from the lack of complete assurance that the prefixes are unique. There is a small possibility that the same locally assigned IPv6 Local addresses will be used by two different organizations both claiming to be authoritative with different contents. In this scenario, it is likely there will be a connection attempt to the closest host with the corresponding locally assigned IPv6 Local address. This may result in connection timeouts, connection failures indicated by ICMP Destination Unreachable messages, or successful connections to the wrong host. Due to this concern, adding AAAA records for these addresses to the global DNS is thought to be unwise. Reverse (address-to-name) queries for locally assigned IPv6 Local addresses MUST NOT be sent to name servers for the global DNS, due to the load that such queries would create for the authoritative name servers for the ip6.arpa zone. This form of query load is not specific to locally assigned Local IPv6 addresses; any current form of local addressing creates additional load of this kind, due to reverse queries leaking out of the site. However, since allowing such queries to escape from the site serves no useful purpose, there is no good reason to make the existing load problems worse. The recommended way to avoid sending such queries to nameservers for the global DNS is for recursive name server implementations to act as if they were authoritative for an empty d.f.ip6.arpa zone and return RCODE 3 for any such query. Implementations that choose this strategy should allow it to be overridden, but returning an RCODE 3 response for such queries should be the default, both because this will reduce the query load problem and also because, if the site administrator has not set up the reverse tree corresponding to the locally assigned IPv6 Local addresses in use, returning RCODE 3 is in fact the correct answer.