Postfix, Dovecot and SASL configuration for Virual hosts!

Configuring server to send and receive with postfix was interesting. Following was involved.
* Installation and configuration of Postfix, Dovecot and SASL and their dependencies
* Writing shell scripts for adding new email addresses for Virtual hosts
* Dealing with "Relay access denied" was finally fixed after a lot of internet search and configuration updates. It was a learning experience.