Take a look in System Settings -> Module Config -> Actions upon server and user creation – there’s an option at the top called “From: address for email sent by Virtualmin” that has the email address to use, you may need to tweak it.
-Eric
Thanks but it seems to be a system problem. I’ve seen the same behavior in BIND and when I run php scripts that lookup the hostname it’s displayed as server.domain.com.domain.com
Just a thought dkcp. Have you checked your DNS records, in particular your NS record for your mail server to make sure it is properly terminated with a "." I have been caught by this a few times and the problem seems similar.
Thanks guys and I found it eventually. It seems to go back to when I set up the server. Somehow the domain got doubled. Eventually I found and fixed that but the problem was still there. It turned out that the hostname was explicitly set in postfix and as such wasn’t updated when I fixed it at the root so to speak.