How to Set Up an Email Server

by John Wu

An email server actually contains several functions. Email server software sometimes combines those parts into one piece for ease of installation. However, large email installations have to put each function on a separate mail server or even multiple mail servers. Depending on the size of the email user population, it may be advantageous to have multiple mail servers rather than just one.

A domain name service (DNS) needs to be set up for the domain being hosted by the email server. In particular, the mail exchange (MX) DNS records for the domain name(s) need to point to the email server being set up. Without a MX record for the domain, emails bound for the domain will not know which email server to go to. DNS may be configured from the domain name service provider's website.

Set up the mail transfer agent (MTA) on the mail server. The MTA receives email from the Internet via the simple mail transfer protocol (SMTP) which is on Port 25. The DNS MX record will point to the host running the MTA.

Set up the mail delivery agent (MDA). The MDA delivers the email to the correct user or otherwise processes it. For example, junk email is filtered at the MDA layer. The MTA often includes a limited version of the MDA.

Set up the mail user agent (MUA). The MUA is the program email users access to read their emails. Eudora and Microsoft Outlook are two popular MUA that resides on the email user's desktop computer. There are also web-based MUAs, such as the front-end clients used by Hotmail, Yahoo! mail and Gmail users.

Test the email from the Internet all the way to the email user's mailbox. If the emails don't arrive, inspect the bounced email carefully for configuration errors.

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About the Author

John Wu is a writer who has covered computers, health, fitness and business since 2008 for various online publications. He is also an IT manager at a government agency. Wu holds a B.A. in legal studies from University of California, Berkeley and a B.S. in computer science from San Jose State University.

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