Installing a mail server in Red Hat Linux is the easy part; it's the configuration that takes patience, resolve, and some experimentation. Once your mail server is running, it is easy to set up a Post Office Protocol service to allow users to download e-mail to their own workstations.
You can replace Sendmail with Postfix as your mail-transfer agent in Red Hat Linux. To make the transition a bit easier, Red Hat provides the alternatives feature. Alternatives let you to switch one MTA for another by linking essential files to the package you choose.
Sooner or later, an alias definition in /etc/aliases will become unmanageable. At this point, mailing list software, such as majordomo, can provide the flexibility necessary to manage a large distribution list, with the added benefits of archiving, moderation, digesting, and automated administration.