Review: 6 free email servers for small business

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

1 2 Page 2
Page 2 of 2

We tested the free version of SmarterMail Windows-based mail server. SmarterMail is marketed as an 'Exchange-level' mail server. The free version we tested is limited to 10 users on a single domain. While this is the most limited of all the products tested, the free version of SmarterMail may be practical for small offices with just a few users. It is also somewhat unique in that it has all the features of the full version.

By default SmarterMail installs with its own embedded web server and we went with this approach for our first install, which took only a few minutes and prompted only for a minimum of configurations (admin password, IP address, DNS servers as well as basic anti spam and virus setup).

But since the vendor recommends using IIS for a more robust and secure installation, and we aren't very fond of embedded web servers anyway, switching to this setup was an easy choice. We installed SmarterMail on a Windows Server 2008 R2 box. The installation is the same regardless of the server you're using since the switch to IIS happens after the initial install. This involves stopping, then disabling the built-in web server and creating a site in IIS for SmarterMail. The only pre-requisite we needed to install was the .Net Framework 4.0.

Creating new domains is done from a tabbed screen with selections ranging from the basics, such as domain name and admin password, to more advanced settings such as throttling and event restrictions. Users are set up much the same way and while there are a number of custom settings that can be utilized, a basic account just needs an entry for user name and password. We found that for the most part you can accept default values and come back to tweak later.

SmarterMail is built for Webmail and has an intuitive interface that probably won't have you missing Outlook anytime soon. In addition to email you can manage calendars, contacts and instant messages from any device with a browser. Should you desire to use a desktop mail client instead, you can use a client such as Thunderbird or Outlook.

We tested with a Thunderbird client and were able to send and receive mail with no issues. SmarterMail also has a flexible auto-discovery feature that can be used on both desktops and mobile clients which allows a device to be configured by using just the email address and password. The rest of the configuration is automatically downloaded from the mail server.

SmarterMail has mobile support for most of the common devices such as Androids, Apple devices, BlackBerry and Windows Mobile devices. It also has built-in instant messaging and a mobile interface that was created for smartphones, making easier to navigate.

Server administration is accomplished through a browser-based interface allowing administrators the flexibility of remote access, something that is helpful, especially for smaller businesses where an IT admin might not be onsite at all times. The Flash tutorials provide a quick-start guide for new users, something we found helpful.

SmarterMail can integrate with spam solutions such as SpamAssassin and Trend Micro, but it can also be configured to use other methods such as black/grey/white listing, custom headers, SMTP blocking, SPF and others.


Zarafa is maintained by a group in the Netherlands which specifically markets its collaboration server as an alternative to Microsoft Exchange. It features an AJAX based browser-based client with a PHP backend intended as replacement for Outlook. Zafara claims to be the only open-source collaboration platform with a MAPI-based architecture. Zarafa leverages existing open source technology such as Postfix as its MTA and stores all data in a MySQL database.

Zarafa runs on several Linux flavors such as Debian, SUSE, Red Hat and Ubuntu. We chose Debian Version 6.05. As the user manual states there are a 'bunch of requirements' that need to be met such as installing MySQL, Apache (or other PHP web server) and an SMTP server such as SendMail or Postfix. Installing a LAMP stack accomplishes a bulk of these prerequisites. Zarafa can be installed in four ways (distro, install scripts, manual and from source). We decided to use the install script, which, at least for our single server test, turned out to be the shortest route.

The Zarafa server is configured by a using a system-wide .cfg file. Users are typically set up using the DB plugin or if you wish to integrate with the Linux server you can use the Unix plugin. You can also manage users by using the LDAP protocol to link to solutions such as Active Directory or eDirectory.

Although Zarafa offers several commercial versions of their server, we found the open source version to be quite capable even if it lacks some of the features of its commercial counterpart (calendaring, unlimited Outlook clients and multi-server support).

Communication between the client and server is based on Simple Object Access Protocol technology. In order to communicate with mobile devices, Zarafa uses what it calls Z-push. Z-push is an open-source implementation of Microsoft's ActiveSync protocol and it works with devices running iOS, Android, Windows Mobile, Nokia and others.

The Z-Merge framework enables developers to integrate Zarafa WebApp easily with CRM, DMS and other solutions. For instance Zarafa can integrate with SugarCRM and recently a Dropbox plug-in was made available.


Citadel has its roots as a bulletin board system platform from the early 1980s, but has since developed into a groupware product with support for features such as calendaring, addressing and instant messaging in addition to email. Unlike most, if not all, other open source mail servers, Citadel is a custom purpose-built product.

For instance, it does not use Postfix, but it has its own custom code written in C for SMTP purposes. The company targets SMBs looking for a self-contained, low maintenance and fully integrated stack.

We installed Citadel on a server running Debian 6.05 and found it was easy to install compared to some of the other Linux products we'd been wrestling with. Management is browser-based and can be customized to display only the functions you wish to use. After creating a test domain, we set up users, which can be completed with a short two-step wizard, or manually.

The calendar and task functionality seems solid, although it would be nice to click into the calendar to create a new entry. We liked the notes section where you can put up small Post-It like notes of different colors with reminders.

Overall we found the interface to be functional and easy to use; it might not feel as Web 2.0 modern as some of the other web interfaces we tested, but our preview of the upcoming release showed major UI improvements on the way.

Citadel is also available as a virtual appliance that can run on KVM or VMware. These pre-built Linux installations are ready to go out of the box, complete with anti-spam and anti-virus. Load balancing is also available, but we tested with a single server setup.


Axigen's free mail server provides an alternative to open source. Just like SmarterMail it is a full version of the commercial offering, but with limits on capacity (100 users). It is available for RPM distros, Debian, Mandriva, FreeBSD, Solarias and Windows Server. We decided to go with Windows 64-bit version and installed it on a Windows Server 2008 R2 server. The installation is available as an .MSI file and the installation was very simple with a prompt for Admin password and which protocols to use.

Axigen is managed from a Web interface that we found comprehensive and easy to navigate. The use of a collapsible menu keeps the navigation less cluttered, but keeps all functionality at your fingertips. Axigen provides all features you would expect in a complete mail server. It has built-in support for Kaspersky anti-virus and anti-spam and it can be integrated with other solutions such as CommTouch, SpamAssassin and ClamAV.

Setting up a new domain and new users was easy. Both offer a 'quick create' option where you enter just the basics or you can expand the property sheet to modify properties to a very granular level. For instance, you can specify which protocols are available for a user, effectively only allowing the POP or Web access. The AJAX Web client interface is clearly meant as an Outlook replacement in not just look and feel, but also functionality. If you are used to Outlook, you will feel right at home with not much need for adjustment.

Another neat feature, especially when you're not familiar with a product, is the contextual help that is displayed by default in a right-hand column. It is not obtrusive like a pop-up would be and it has just enough information to be useful. Once you become familiar with the interface, you can minimize the help function.

Perschke is CSO for Arc Seven Technology. She is also an experienced technical writer, and has written numerous white papers for a number of organizations, including Fortune 500 companies. Susan can be reached at

Copyright © 2012 IDG Communications, Inc.

1 2 Page 2
Page 2 of 2
The 10 most powerful companies in enterprise networking 2022