Making your Piratefish relay outbound mail

Alexey Soukhanov writes:

First of all, let me thank you for your job at website piratefish.org

I was looking for a good guide that can help a Microsoft oriented worker like me to install a Linux machine in our office. I just started the installation and in my network the mail relay server is in a DMZ with real IP (my MX record point this ip address) so mail servers that do reverse look up can return mail to me that doesn't come from this ip.

My FW configuration allows traffic from exchange to mail relay in DMZ only.

Here is a diagram of my mail transport:
INTERNET -> FW -> MAILRELAY IN DMZ real IP -> EXCHANGE LOCAL IP

How can I configure postfix to allow traffic from exchange to Internet and allow it only for exchange?

Like this:
EXCHANGE -> MAILRELAY -> FW -> INTERNET

Johnny Writes:

In webmin, go into the postfix configuration, General Options section.

Find a section called "Local Networks" - it should appear as 127.0.0.0/8

Edit this so as to include the networks you wish to trust - for example:

127.0.0.0/8 192.168.1.0/24 172.16.0.0/16

Click on Save and Apply, and you should be good to go. The Piratefish should then be able to relay email outbound from your mail server. Be sure to configure your mail server so that it relays mail to the piratefish. In some setups this is called the "smart host" .

Thanks Alexey!