On 6/26/2012 1:04 PM, lutz.niede...@gmx.net wrote: > > Hi! > > We do have two external mail relays (MX 10 mx1 & MX 20 mx2) that accept mails > for our domains, do lots of checks and relay them via a secure channel > through the firewall into our network. Inside and outside we use postfix. > > When sending mails out, we use the same way: send them from our internal > network to one (mx1 only) of our mail relays via secure channel. This > external postfix does - again - a lot of thing like DKIM etc. This outside > postfix on mx1 then sends mails into the world. > > The internal postfix sends the mails to mx1 using "default_transport" (using > a customized incarnation of smtp in master.cf). > > What we thought is that we could use mx2 for outgoing mails, too. This would > be wise if mx1 is down (what sometimes really happen). > > But I find no setting like "fallback_default_transport" that can be used like > default_transport in case our default_transport does not answer. > > Can anyone please tell me how we can establish a backup link to our mx2 > working like default_transport for the cases where mx1 is not available? > > Thanks a lot! > -lutzn >
The best solution is to use MX records; that's what they're for. Alternately, look at http://www.postfix.org/postconf.5.html#smtp_fallback_relay -- Noel Jones
