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Review: 6 free email servers for small business

hMail Server (Windows only) comes in first, Citadel (Linux only) is a close second

By Susan Perschke, Network World
September 17, 2012 07:05 AM ET

Page 3 of 7

The bundling caveat applies mostly to products that run on Linux, since Windows products usually install from a single file, although this is by no means a guarantee of foolproof results. One of the products that bit the dust and was unceremoniously ejected from the test lab was a Windows product so fraught with twists and turns and endless tweaking of configuration files and environment variables that it made the Linux bundles seem like a cake walk. Beware the lure of a glitzy website promising mail server Nirvana - in a market where every free ride ends at the vendor's toll booth for commercial support, simplicity is the exception and not the rule.

A note about MTAs

While we're on the subject of dependencies, it should be noted that two of the products we tested, Apache James and Zarafa, use third-party MTAs (mail transfer agents). The name is apt - the MTA is tasked with the usually invisible job of transporting mail from one place to another over SMTP. Invisible, that is, until it doesn't work, whereupon it quickly becomes apparent that this little nondescript utility is in fact the one indispensable component every mail server requires to function.

You can send email using nothing more than an old-fashioned telnet session and an MTA; conversely the most elaborate email setup without a functioning MTA will send email precisely nowhere. MTAs are true workhorses that have the capacity to transfer hundreds of emails per second. Some of the more popular MTAs include Postfix, Exim and Sendmail.

Postfix runs on a variety of Unix/Linux flavors and it is also packaged with several of the mail server solutions we tested. Exim is currently the MTA of choice in all Debian Linux systems. It has been around since the mid-1990s and is highly configurable. Unlike Postfix, it does not have a centralized mail queue and thus might not be the best choice for installations where the mail queue becomes very large.

Unlike Postfix, which is still open-source only, Sendmail has taken a commercial path with different email products and solutions. However, Sendmail continues to update and support their open source solution as well.

Here are reviews of the individual products:

How to choose a mail server

Features chart         
    Click to see: Features chart


We installed hMailServer on Windows Server 2008 Standard Edition (32-bit). During installation there are just a few prompts and installation is completed in a few minutes. HMailServer has most of the basic features a SMB would want or need (SMTP, POP and IMAP). There is no native webmail included, but hMailServer works with any web mail system that supports SMTP, POP and IMAP.

This can be a PHP-based system running on Apache such as SquirrelMail or ASP/.NET-based system running on MS IIS. All configuration is performed from a single clean interface with expandable sections for domains, users, protocols, spam configuration, server status, etc. By default hMailServer installs with a SQL Server Compact database, but it can also be used with a standard version of MS SQL Server, MySQL or PostgreSQL.

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