-----Original Message-----
From: owner-ietf-smtp(_at_)mail(_dot_)imc(_dot_)org
[mailto:owner-ietf-smtp(_at_)mail(_dot_)imc(_dot_)org] On Behalf Of
ned+ietf-smtp(_at_)mrochek(_dot_)com
Sent: Friday, December 17, 2010 9:26 AM
To: SM
Cc: John R Levine; IETF SMTP list
Subject: Re: A few ipv6 questions
A dual stack client would favor the IPv6 address and try to connect
to it first.
Nope, not necessarily. In some cases it is entirely reasonable for a dual
stack
client to try IPv4 before IPv6. Or use some other criteria to decide which
addresses to try.
For simplicity one might try them in the order returned by the resolver, for
example: Walk through the answer section and, if A, use AF_INET; if AAAA, use
AF_INET6.