KMS: The Mail Server Goes Virtual

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Kerio Mail Server: Multi-platform mail server with support for mobile devices.

E-mail is one of the oldest technologies on the Internet, and yet today’s mail servers must support a wider variety of features than ever. For one, e-mail has gone mobile, and users expect to be able to manage their messages from mobile devices and messaging experience. Competing with Exchange means providing customers with a familiar thin clients. Then, there is the seemingly immovable elephant in the room, Microsoft, whose Exchange server and Outlook client combination have defined the corporate environment.

Kerio Mail Server (KMS) 6 is on the leading edge of the curve on all these fronts, and outdoes Microsoft Exchange in a notable way: cross-platform support. In addition to Windows, Mac OS X, and RedHat or SUSE Linux, KMS is available as a VMware virtual appliance (built on CentOS 5.2). This means it can run in its own sandboxed virtual machine on top of any VMware-supported platform.

The Windows version of KMS 6, for most 32-bit Windows platforms, is a 65MB download that installs into a 130MB footprint. You can administer the server locally or remotely using Kerio’s Administration Console, or a Web browser, although the Console is more full-featured. If you’ve ever used a Kerio server product before, there is a consistent interface to their Administration Consoles that is clean and easy to navigate. The install wizard configures an initial mail domain with sensibly cautious defaults.

Many e-mail customers today are looking for mobile access, which often means pushing messages to smart phones. KMS 6 supports Microsoft’s Exchange ActiveSync protocol for pushing mail to the iPhone, Windows Mobile devices and Palm OS. Blackberry devices use a different push protocol, called NotifyLink, which KMS 6 supports. Phones that don’t support push mail may still be able to access KMS through its mobile friendly lightweight Webmail interface or standard POP3/IMAP protocols.

Besides mobility, security is paramount in today’s e-mail environment, where some 50 percent or more of messages are spam that may contain virus-laden attachments. KMS takes a somewhat novel approach to anti-virus protection, with support for two layers of anti-virus (AV) scanning. If you choose a KMS license with support for McAfee AV, its scanner is integrated into the server. The server also includes plugins for AVG, NOD32, SAVI, Avast, Kaspersky, Symantec and Clam AV. Although dual-AV protection sounds nice on paper, in practice the best part of this feature is that if you already subscribe to a service other than McAfee, you can forgo the cost of bundled AV and continue using your existing AV provider.

KMS’ anti-spam defense provides a comprehensive battery of tests that can be run against incoming mail to produce a spam score. Based on this score you can define further action, from tagging messages in the header and subject fields, bouncing or quarantining. To generate a spam score, KMS can consult real-time blacklist (RBL) databases, custom message parsing rules and SpamAssassin bayesian heuristics, as well as using sender authentication protocols like “caller ID” and SPF.

For purposes of data integrity and legal protection, KMS includes both backup and archiving features. Scheduled backups protect against lost messages, while archives store all incoming and outgoing messages in a separate location so they cannot be retroactively deleted or modified by mailbox owners.

Today’s corporate e-mail users often do much more than send messages. Thanks to the prevalence of Outlook, customers expect to use calendaring, create tasks, notes and contacts, plus share public folders. KMS 6 supports all of the above through most of its methods of interaction. Desktop or laptop users can load the rich Webmail interface, which includes an Outlook-like drag-and-drop and access to all groupware features. Alternatively, you can use Outlook itself via Kerio’s connector, a separate but free download that supports offline groupware access with sync.

Although there are less costly and even open source e-mail servers, Kerio MailServer 6 will appeal to the organization looking for a turnkey Exchange replacement that can run on non-Windows platforms and is easy to administer.

Pros: Well-designed; Accessible administration console; Support for third-party AV scanners; Exchange compatibility.
Cons: Licensing costs for larger number of mailboxes.

Reviewed by: Aaron Weiss
Original Review Date: 09/05/2008
Original Review Version: 6.5.2

This article was first published on ServerWatch.com.