If your mail server serves mobile or remote clients, you will probably run into the “port 25 block” problem that is sweeping the ISPs of the nation. To make life easier for my mobile users, I opened as second SMTP listener on an alternate port that will not get blocked, and configured their email clients to send via that port. To do this on OS X Server (or any Postfix installation), edit the file /etc/postfix/master.cf and add the following line in along with the other services:
2525 inet n - n - - smtpd
You can change the “2525″ to whatever alternate port you want to use.
Good Stuff that helped me out a lot but I have a problem, perhaps you know the answer
I have domain1.com and I have the email address admin@domain1.com working great…
Next, under hosting in the Mail Administrative section I add domain2.com as a Local Host Aliases and create a new user say Alex to have alex@domain2.com that works but at the same time I now have alex@domain1.com…. Any ideas??
Thanks in advanced