Configuring postfix to handle email on multiple domains without being an open relay

Question

There was a question about open relays asked previously.

I have a new CentOS 6 server handling multiple domains for several customers.

On the previous server (which was running CentOS 4), I had sendmail configured to handle incoming mail for several domains.

The goal is to replicate the old functionality on the new server - but my experience with administering mail is limited.

Ideally, I want a given mailbox to be addressable via any of the allowed domains. Eg [email protected] & [email protected] should be the same inbox (since the user exists on the same server).

Ultimately, I anticipate we will be splitting mail and web traffic, but the traffic demands just aren't that high yet.

How can postfix be configured to handle multiple incoming domains for the same mailboxes?

Solution

In your main.cf you need to set your mydestination parameter.

it should have something like:

mydestination = $myhostname, localhost.$mydomain, $mydomain

You need to change it to:

mydestination = $myhostname, localhost.$mydomain, domain.net, domain.com

More info on the parameter:

http://www.postfix.org/postconf.5.html#mydestination