Enabling a domain-wide Mail Transport Agent (MTA) and testing your SMTP configuration with Telnet

In this recipe, we will learn how to configure Postfix as a domain-wide MTA and test your SMTP configuration with Telnet.

Postfix is now the default MTA for CentOS but by default it does not accept network connections from any host other than the localhost. This is quite restrictive. So the purpose of this recipe is to show you how to configure Postfix to accept incoming connections on all interfaces, to setup a mailbox for each user, to enable a domain-wide MTA, and to test your resulting SMTP configuration with Telnet.

Getting ready

To complete this recipe you will require a working installation of the CentOS 6 operating system with root privileges, a console based text editor of your choice and a connection to the Internet in order to facilitate the download of additional packages. It is expected that your server will be using a static IP address that it maintains on one or more system user...