Kerio is tops for Mac support

With Outlook users taken care of in one manner or the other, we wondered how each of these products would deal with Macintosh users. While Windows Outlook is well-covered, Microsoft's Exchange client for the Macintosh, Entourage, is not supported by most of the products we looked at, so we decided to to focus on native support. For pure e-mail, the Macintosh platform has multiple IMAP (and POP) clients available, so reading and sending e-mail was not going to be a difficult. Where the problem comes in is in contact and calendar management. Apple's OS X has a built-in pair of applications for contacts ("Address Book") and calendars ("iCal"), so any extension would have to accommodate those products.

Because iCal supports the new IETF standard for calendar sharing, CalDAV (Calendaring extensions to WebDAV), we hoped to find products with extensive support for it. Macintosh Address Book has specific support for synchronizing with Apple's own sharing service, MobileMe, as well as with Exchange, Yahoo and Google applications. However, in the absence of an Address Book version of the CalDAV specification, there's no standard you can point to for Address Book synchronization of contacts.

In our testing, the clear winners for Macintosh support were Kerio MailServer and Zimbra Collaboration Suite. Both have very complete CalDAV implementations, including not just sharing and updating calendars, but also group scheduling by sharing free/busy time information. In addition, both have Macintosh specific synchronization plugins for Apple’s iSync tool, providing a very clean synchronization of contact information. We tested both these tools and watched contacts flow from the Macintosh into both mail servers, then be immediately visible to webmail and Outlook clients.

Scalix Enterprise Edition and CommuniGate Pro also include CalDAV support, but the versions we tested don't include all of the options. For example, Free/Busy time sharing, important in group meeting scheduling, didn't work in either product. Neither has support for Macintosh Address Book contact synchronization. MailSite Fusion offers an older calendar sharing standard, WebDAV, which is a subscription-only option — Macintosh users can read their calendars off of a MailSite Fusion server, but can't change them. MDaemon has no WebDAV, CalDAV, or other Macintosh-specific support.

Mobile synch

Finally, we turned to mobile device synchronization. While proprietary schemes abound, such as those used by Palm OS devices, the dominant standard for mobile device synchronization today is ActiveSync, available on Windows Mobile and iPhone devices.

CommuniGate Pro, Kerio MailServer, MailSite Fusion and Zimbra all support ActiveSync, and we were (eventually) able to get all of them to work properly with our Windows Mobile and iPhone test devices. Although making ActiveSync work often took some doing, when it did start working, we found it to be an amazing feature. IPhone users will especially love ActiveSync, because it reduces the need for them to keep tethering their iPhone back to iTunes just to keep calendar and contact information in synchronization. Scalix Enterprise Edition has ActiveSync in beta, but did not send it for testing. MDaemon does not support ActiveSync, but Alt-N said it plans to release it in June.