Finding the best of the basic messaging feature sets

The set of basic features that comprise a business e-mail server today are simple e-mail access and full support for multiple delivery protocols, including SMTP, POP and IMAP. Additionally, because Exchange also includes contact management and calendaring tools in its basic bundle, we also considered those must-have features.

Not surprisingly, we had no significant issues in finding these basic tools across most of the products tested. The first product that didn't meet these basic requirements was MailSite Fusion, which doesn't support an important IMAP feature called "Idle", which was first developed in 1997 and is used by e-mail clients to support a concept referred to as push e-mail: instant notification of an incoming e-mail. Without IMAP Idle, the alternative is for the client to continuously poll the e-mail server for new mail. Even this deficiency, though, may not be important to you if you have no e-mail clients (such as mobile phones) making use of IMAP Idle or if you don't consider push e-mail critical.

However, missing IMAP Idle is a fairly small offense compared with what we discovered in Kerio MailServer, which does not completely support IMAP SEARCH, the IMAP protocol command used to search messages within a folder or set of folders. This means that if you want to go find something inside of an old message you've got filed on your IMAP server, then this mail server isn't for you. This same lack of search capability also extends to the webmail interface.

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The set of basic features that comprise a business e-mail server today are simple e-mail access and full support for multiple delivery protocols, including SMTP, POP and IMAP. Additionally, because Exchange also includes contact management and calendaring tools in its basic bundle, we also considered those must-have features.

Not surprisingly, we had no significant issues in finding these basic tools across most of the products tested. The first product that didn't meet these basic requirements was MailSite Fusion, which doesn't support an important IMAP feature called "Idle", which was first developed in 1997 and is used by e-mail clients to support a concept referred to as push e-mail: instant notification of an incoming e-mail. Without IMAP Idle, the alternative is for the client to continuously poll the e-mail server for new mail. Even this deficiency, though, may not be important to you if you have no e-mail clients (such as mobile phones) making use of IMAP Idle or if you don't consider push e-mail critical.

However, missing IMAP Idle is a fairly small offense compared with what we discovered in Kerio MailServer, which does not completely support IMAP SEARCH, the IMAP protocol command used to search messages within a folder or set of folders. This means that if you want to go find something inside of an old message you've got filed on your IMAP server, then this mail server isn't for you. This same lack of search capability also extends to the webmail interface.

The lack of Active Directory integration in some of these products came as a surprise. Although these mail servers are often pitched as an alternative to a Microsoft world, there's no reason that they can't coexist in a Windows domain. Both the servers we installed on Windows, MailSite Fusion and MDaemon, would link to Active Directory — no surprise there. But the Linux player CommuniGate Pro wouldn't talk to Active Directory at all, and the Zimbra Collaboration Suite let us use Active Directory for authentication but not for storage of any user attributes.

The most involved Active Directory interactions arose when we were working with Kerio MailServer and Scalix Enterprise Edition. Both of these products can put hooks directly into Active Directory and it can then be used as the product's own directory service. If you select this option, the normal Active Directory user management tools, such as "Active Directory Users and Computers," can be used to manage user properties in the Kerio and Scalix servers, bringing those more into line with Exchange's user management scheme.

Our Scalix server linked to Active Directory without any technical problems, although the process is fairly arduous. Unfortunately, not all user attributes necessary to maintain Scalix users are contained in Active Directory, so even if you do choose to link Scalix and Active Directory, you'll occasionally have to dive into the Scalix management system to change some privileges or set visibility of some information in the mailbox. With Kerio MailServer, though, we were unable to connect with Active Directory. Kerio's technical support confirmed that this was known not to work, and told us that this would be fixed in the next major release.