[Trilug-ontopic] IPv6 mail on pilot

[Aaron Schrab]

Even though pilot now has IPv6 connectivity the mail services on it are 
only listening on the IPv4 address.  So other systems with IPv6 
connectivity are likely trying that first, then falling back to v4 when 
that connection is denied.  Both postfix and dovecot are pretty easy to 
get running with both.

For postfix, just adding "inet_protocols = ipv4,ipv6" to the main.cf 
should suffice.  Although adding IPv6 networks to the mynetworks 
variable would likely be a good idea as well.  My configuration 
automatically had "[::ffff:127.0.0.0]/104 [::1]/128" included in that to 
allow the IPv6 loopback address and the IPv4 loopback network mapped to 
IPv6.  Adding "2001:470:8:11ec::2/64" would allow other hosts on the 
trilug network to relay mail through pilot.

For dovecot it should just require changing the listen and ssl_listen 
directives.  On my server I just have "listen = *, [::]" at the top 
level of my dovecot.conf, telling it to listen on all IPv4 and IPv6 
addresses with the default port for each protocol.  To do the same on 
pilot, the listen and ssl_listen directives in the "protocol imap" 
section would need to be removed.  Since the default ports are being 
used, this shouldn't be a problem.