The most important part of any e-mail system is the MTA. This system is responsible for handling delivery of e-mail messages, both outbound and inbound. It can also be the downfall of your mail system if it is improperly configured, which could result in your system being used for sending SPAM mail to other destinations.
One of the original and most well known MTAs is Sendmail, which dates back to 1983. It is a very powerful tool, and unfortunately very easy to get wrong. In fact, the configuration language for Sendmail is so obtuse that there is actually a macro language called m4, which is commonly used for generating Sendmail configurations. M4 makes configuring Sendmail much simpler, but there are other options available which natively use a sane configuration language like Postfix.
The great thing about Postfix as opposed to a number of other SMTP servers is that it is built with a set of sane, safe defaults. Additionally, any setting, which...
