Dear All I am planning to setup mail server for my domain. Which one is preferred postfix or sendmail. I came across a link * http://ostechnix.wordpress.com/2013/02/08/setup-mail-server-using-postfixdovecotsquirrelmail-in-centosrhelscientific-linux-6-3-step-by-step/ * for postfix mail setup. It says, Prerequisites: - The mail server should contain a valid MX record in the DNS server. Navigate to this link how to setup DNS server<http://ostechnix.wordpress.com/2013/01/25/setup-dns-server-step-by-step-in-centos-6-3-rhel-6-3-scientific-linux-6-3-3/> . - Firewall and SELinux should be disabled. I have disabled iptables as my m/c is behind the firewall. It says I need to disable firewall. Is it really required. Kindly let me know. Best Regards Austin