Jaroslaw Rafa:
> Dnia 31.10.2019 o godz. 21:27:46 Benny Pedersen pisze:
> > how will postfix handle connections if recipient domains see ip in
> > rbl blacklist, will it be trying agin until all ips on recipient
> > domain is tryed ?
> >
> > does it make sense ?
> >
> > will first reject just win on dual stack ipv4 / ipv6 hostname ?
> >
> > i ask this since i like to know what to do with that problem, if at
> > all anything
>
> >From what I have seen in the logs, if both IPv6 (AAAA) and IPv4 (A)
> addresses are available, Postfix tries to connect on IPv6 first. If it can't
> connect (for example because your sending server doesn't have IPv6 routing
> :)), it falls back to IPv4.
By default:
smtp_address_preference = any
i.e. the Postfix SMTP client randomly selects between IPv4 and IPv6.
With Postfix 3.3 and later, Postfix is smarter about sites that
list more IPv6 addresses than IPv4 addresses (or vice versa). In
that case, Postfix will try to use equal numbers of IPv4 and IPv6
addresses (or vice versa), so that mail won't get stuck if, for
example, IPv6 is down.
Wietse
