The IESG has approved the Internet-Draft 'DHCPv6 Options for SIP
Servers' <draft-ietf-sip-dhcpv6-01.txt> as a Proposed Standard. This
document is the product of the Session Initiation Protocol Working
Group. The IESG contact persons are Allison Mankin and Scott
Bradner.
Technical Summary
This draft specifies two DHCPv6 options that allows SIP clients
to locate a local SIP server that is to be used for all outbound SIP
requests, a so-called outbound proxy server. SIP clients MAY contact
the address identified in the SIP URL directly, without involving a
local SIP server. However in some circumstances, such as particularly
when a firewall is present, SIP clients need to use a local server
for outbound requests. The SIP DHCPv6 option (for use in IPv6
environments) is one of many possible solutions for locating the
outbound SIP server; manual configuration is an example of another.
This document defines two DHCPv6 options that describe a local
outbound SIP proxy: one carries a list of domain names, the other
a list of 128-bit (binary) IPv6 addresses.
Like the DHCPv4 option for this function (currently in the RFC
Editor's queue), the SIP DHCPv6 option uses RFC 1035 encoding
(Section 3.1 of RFC 1035), after careful review of the design
by the DHCP working group and the Internet Area Directors.
Working Group Summary
The working group supported advancement of this specification.
Protocol Quality
The document was reviewed for the IESG by Allison Mankin.
During IETF Last Call, it was noted that the consequences
of a rogue DHCP server might be quite serious for SIP clients.
RFC 3118 provides a means for mutual authentication
between a DHCP client and server, and there is a plan for
development of a specification for clients to authenticate
their servers without the mutual authentication requirement.
This document inherits the Security Considerations of the
DHCPv6 specification (to be announced at the same time as
this). In addition, the SIP RFC (draft-ietf-sip-rfc2543bis-09.txt),
currently in the RFC Editor queue, advises SIP clients to
authenticate servers they use, by careful checking of the server
certificate provided by use of a TLS connection for the client-to-
server communication.
