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
