Install & config postfix on CentOS

gistfile1.txt

Step 1 - Install
# yum remove sendmail
# yum install postfix

Make postfix as default MTA for your system using the following command
# alternatives --set mta /usr/sbin/postfix

If above command not work and you get the output as “/usr/sbin/postfix has not been configured as an alternative for mta“. Use below command to do the same else skip it
# alternatives --set mta /usr/sbin/sendmail.postfix

Step 2 - Config /etc/postfix/main.cf
    myhostname = mail.tecadmin.net
    mydomain = tecadmin.net
    myorigin = $mydomain
    inet_interfaces = all
    mydestination = $myhostname, localhost, $mydomain
    mynetworks = 127.0.0.0/8, /32
    relay_domains = $mydestination
    home_mailbox = Maildir/
    
Step 3 – Restart Postfix Service
# service postfix restart
# chkconfig postfix on

Step 4 – Open Firewall Port
iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 25 -j ACCEPT
# iptables -A INPUT -m state --state NEW -m udp -p udp --dport 25 -j ACCEPT

Step 5 - Test
# php -a
# mail ('you@example.com', "Test Postfix", "Test mail from postfix");
# exit ();