Hey all,

We run a Postfix mail server on Fedora 5 to function as an outgoing mail server, which works great with our setup. Nobody needs to connect directly to it, all the work is done by other applications, it just needs to be able to send mail out.

The problem we're having is when emails that are sent out bounce back. We use a valid email address as the reply-to address, and when a message bounces Postfix attempts to look up the domain name (our own) and send the mail that way. Trouble is, the public IP it gets for the MX record is not reachable from the internal network, so it times out. As a result, nobody knows when a message bounces.

My first reaction was to edit the /etc/hosts file so it sends mail to our internal IP instead of a public IP. However, it seems that Postfix does not read the hosts file, so this didn't help. Tried disabling DNS lookups, and while that sorta worked, other mail didn't sent out properly.

So, what I'm looking for is a way to tell Postfix to send mail for our own domain to a specific IP address without causing other outgoing mail to have any problems. Any ideas on what else I could try?

As mentioned, system is running Fedora Core 5 and Postfix version is 2.2.8.

Thanks.

Sounds like you need to define a transport: