Jeroen Geilman: > On 05/18/2011 08:52 PM, Vick Khera wrote: > > On Wed, May 18, 2011 at 2:30 PM, evilgh...@packetmail.net > > <evilgh...@packetmail.net> wrote: > >> I'm certainly open for any suggestions for accommodating my goal of > >> applying an > >> IPv4 relayhost to non-IPv6 capable traffic if there is such a way to > >> accomplish > >> this goal with the existing configuration directives. > >> > > What if you do this: eliminate the ability of your mail server to send > > SMTP over IPv4, possibly by removing any IPv4 address from it, or > > firewalling that ability away. > > > > Set up fallback_relay on this host so that all mail that did not make > > it on the first try goes to your relay host. There will be *some* > > IPv6 capable traffic sent that way as the result of transient > > failures, but it will be mostly messages that require IPv4. > > Limit THIS postfix to ipv6 exclusively. > Set up a second instance with both ipv4 and ipv6. > Set the fallback-relay to the second instance. > > inet_protocols = ipv6 > fallback-relay = [::1]:25025 > > And on the second instance: > > inet_protocols = all > relayhost = [your.ipv4.relay.host] > > And in master.cf: > > ::1:25025 inet - - - - - smtpd
This should be possible with one Postfix instance: /etc/postfix/main.cf: relayhost = /etc/postfix/master.cf: smtp unix - - n - - smtp -o inet_protocols=ipv6 -o smtp_fallback_relay=your.ipv4.relay.host Assuming that your.ipv4.relay.host is reachable via IPv6. No firewalling needed. Wietse