I have installed Postfix, Dovecot, and Squirrelmail on a CentOS 5.5 machine. In Squirrelmail a user can send mail, but he is not receiving replies. There is nothing relevant in the maillog other than the user's (successful) login attempts. I am at loss, I have been following tutorials such as the Perfect Server [1] series and other Google results, but I cannot get this thing to receive mail. What should I be checking?
Thanks!
[1] http://www.howtoforge.com/perfect-server-centos-5.5-x86_64-ispconfig-2