On Tue, May 24, 2011 at 11:42:47AM -0700, Ray Dzek wrote:
> When I change the inet_interfaces = smtp.specialized.com on the primary
> inbound instance the mail comes in, but can't find its way out of the box
> to relay to our internal Exchange server. If I leave inet_interfaces =
> all mail works both ways, but then I can't start the second interface
> as I am already bound to port 25 on all 3 interfaces. I am assuming I
> am missing something silly here.
http://www.postfix.org/STANDARD_CONFIGURATION_README.html#firewall
In some installations, there may be separate instances of Postfix
processing inbound and outbound mail on a multi-homed firewall. The
inbound Postfix instance has an SMTP server listening on the external
firewall interface, and the outbound Postfix instance has an SMTP
server listening on the internal interface. In such a configuration
is it is tempting to configure $inet_interfaces in each instance
with just the corresponding interface address.
In most cases, using inet_interfaces in this way will not work,
because as documented in the $inet_interfaces reference manual,
the smtp(8) delivery agent will also use the specified interface
address as the source address for outbound connections and will
be unable to reach hosts on "the other side" of the firewall. The
symptoms are that the firewall is unable to connect to hosts that
are in fact up. See the inet_interfaces parameter documentation for
suggested work-arounds.
http://www.postfix.org/postconf.5.html#inet_interfaces
--
Viktor.
