Deploying Email Services In-House
Deploying UNIX-based email services in a cloud environment is one way for small- or medium-size organizations to deal with the need for an enterprise approach, but not spend too much money.
Setting up a secure private email server isn’t as difficult as one imagines. While securing the bulk of an organziation's email from snooping beyond the per-message level is a challenge, it is do-able. One way of simplifying the email server setup process is with a tool like Helm, which acts as an all-in-one private email server solution. One should consider encrypting the actual contents of an email message with free tools.
Most mail servers made of Mail Delivery Agent (MDA) and Mail Transfer Agents (MTA). MDA software is used to routes e-mail to its destination. MTA software used to transfers e-mail between servers or computers. Apart from MTA and MDA, one needs Antispam, Antivirus, Webmail and other software utilities. The server IP address needs to be properly found (via DNS) and a TSL/SSL certificate configured. It often makes sense to install a database to store user names, email IDs, password and other information -- OpenLDAP comes to mind. Setting up and maintaining a full-fledged email server need not be too a complicated task; it is in the wheelhouse of a good sysadmin. The attached article lists software that enables a Unix-powered VM to run as a mail server out of a box.
This article details how to set up an email server in AWS. Of course, one can run an email server on any Linux system or alternate cloud provider, such as Rackspace.