Minimal postfix/dovecot installation

yum install postfix
chkconfig postfix on
chkconfig sendmail off
/etc/init.d/sendmail stop
/etc/init.d/postfix start

Put these 5 lines in /etc/postfix/main.cf

inet_interfaces = 127.0.0.1, 88.155.666.111    :Listen on loopback and public interface
myorigin = mail.anuj.com         :visible hostname in email
mydestination = mail.anuj.com        :accept email for any@mail.anuj.com
relay_domains = anuj.com        :To relay domain as required (Delete this line if you want to send email to everywhere)
mynetworks = 88.155.666.111/24        :Allow only 88.155.666.111/24 subnet to send/relay email using smtp

allow port 25 and 110 in firewall as necessary

yum install dovecot

edit /etc/dovecote.conf and add following line

protocols = pop3

chkconfig dovecot on
/etc/init.d/dovecot start