This tutorial explains how to setup mail server on ubuntu 14.04 using postfix,dovecot and squirrelmail.
» Postfix ( for sending )
» Dovecot ( for receiving )
» Squirrelmail ( for webmail access ).
Here i have used mail.krizna.com for hostname and krizna.com for Domain . please replace with your domain

Source: Setup mail server on ubuntu 14.04 ( Postfix – dovecot )