A network mail server, or mail transfer agent, is basically your computer network's post office. It's the computer within the network that runs software to send, receive and route incoming and outgoing email messages. You can run an email server on a dedicated machine, or on a machine that you also use to perform other tasks. Email server software is available for Windows NT, Linux and UNIX.

In choosing from a list of email servers, you must consider a variety of factors, including operating system, cost, and speed. There are many choices on the market. To avoid feeling confused or overwhelmed, keep in mind that a mail server basically does three things:

1. An incoming and outgoing mail server maintains a database of users who have email accounts within the network.

2. An email server stores users' email messages.

3. A network mail server sends and receives email according to a set of rules or protocols.

Action Steps
The best contacts and resources to help you get it done

Purchase a network mail server that's right for your system

You need to choose server software that is compatible with the system on which you'll be running your mail server, whether it's Windows, NT, UNIX or Linux. On the other hand, you may want to purchase a dedicated mail server, which often allows you to choose your system.

I recommend: Download a free trial of CMailServer, a user-friendly, Windows compatible mail server program. Axigen is the mail server of choice for Linux users, and can now run on BSD or Solaris platforms-good news for UNIX users. Purchase Axigen's Business Edition, Enterprise Edition or Service Provider Edition, depending on your specific needs. Some dedicated servers let you keep your options open - Dell lets you choose between Linux and Windows if you go with their Poweredge R900 server.

Choose from the ever-increasing list of mail servers and software

Once you know what system you'll be running the server on, choose a mail server for the computer based on cost, convenience, and availability of support. A variety of options are available, including both SMTP and POP/IMAP servers.

I recommend: The MailEnable Enterprise Edition, compatible with Windows, features heightened user control, above-average flexibility and is ideal for businesses who deal with vast quantities of incoming and outgoing email. MailEnable also provides Enterprise Edition customers with limited free support, including two free technical support sessions; further technical support carries an additional fee. IceWarp allows business customers to customize their Merak Mail Server, which runs on Linux and Windows. If you see the value in all offered features, such as security components and an IM server, purchase the Enterprise Suite and receive a discount for bundling.

Ensure that your small business mail server is secure

When you choose a mail server for the computer you'll be using as a virtual post office, make security a top priority. You must have a solid firewall as well as spam and virus protection.

I recommend: The Windows Small Business Server is a comprehensive server solution that includes a mail server with many security features, such as anti-virus and anti-spam protection, and daily and weekly security reports. Best Mail Server, compatible with Windows, offers protection against damaging distributed denial-of-service attacks and spam.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  Maintain the security of your email server by keeping the user database up-to-date and deleting inactive accounts.
• •  For added security, require users to change mail passwords frequently and to choose strong passwords that contain numbers and other symbols in addition to letters.