Exchange alternatives: a group test
Summary: There's a thriving market in email/collaboration servers that aim to replicate the functionality of Microsoft's Exchange. We examine five, including cloud-based and open-source solutions.
Widely viewed as synonymous with business-class email and collaboration, Microsoft's Exchange is far from the only fish in the messaging sea. Indeed, despite its clear market dominance, there are still plenty of alternatives, each capable of delivering much the same functionality — to the same clients, including Outlook users and mobile workers with wireless handsets.
These Exchange alternatives exist because they tend to work out cheaper, as well as being easier to both manage and support. At the same time, they deliver similar levels of scalability and robustness as the Microsoft original.
Two obvious candidates are IBM's Lotus Notes and Novell's GroupWise, both long-term thorns in Exchange's side. That said, we haven't included either product in this group test, mainly because they're rarely seen as like-for-like replacements and we're more interested in products designed to do what Exchange does without making it evident that something else is at work on the server.
To this end, we picked five somewhat less obvious alternatives. One (MDaemon Pro) is a fairly typical Windows-only solution, while Kerio Connect and Gordano Messaging Suite (GMS) can be deployed both on Windows and other hosts. We've also included an open-source product (Zarafa) written for Linux and, because of the increasing popularity of hosted services, Google Apps Premier Edition.
Each has its pros, cons and idiosyncrasies, as outlined below and detailed in the individual reviews, while at the same time sharing a common goal: to do what Exchange does, only more cost-effectively.
What we tested: summary of features

Compare products
Kick off your day with ZDNet's daily email newsletter. It's the freshest tech news and opinion, served hot. Get it.
Talkback
"because they're rarely seen as like-for-like replacements and we're more interested in products designed to do what Exchange does without making it evident that something else is at work on the server. "
What vague spurious nonsense this is. You could equally well say this meaningless phrase about any of the products you have reviewed. To exclude the market leading competitive products from this review is simply inexcusable and makes the whole article worthless.
- Freebusy times is default available, see online demo (http://demo.zarafa.com)
- Migrationtools are available for PST and Exchange. We migrated from Exchange 2000 to Zarafa
- Zarafa can be fully integrated and managed for any kind of LDAP directory server. We use the integration with Active Directory 2008.
For full compatible and stable Outlook support Zarafa is the best solution, because it's fully using the MAPI architecture of Exchange.
delegation, public folders, and syncing of notes, tasks, journals, and distribution lists."
This alone makes me wonder why Google Apps is the winner as a Exchange Server replacement. We use Kerio Connect and it does all that and does it well.
As far Notes and GroupWise are concerned, although Exchnage competitors these really are quite different products in terms of how they're implemented and used. They're also much more high-end and if we had included them we really couldn't have done them justice within the scope of this test, plus it would have meant limiting what we could do with the less well known alternatives which suffer from not getting much coverage anyway. Far better to leave them out of this group test and, possibly, look at them in more depth later.
I accept the limitation of the Google Apps Sync plug-in for Outlook and, although I didn't encounter any during testing, am aware of other issues with Outlook integration in Google Apps. That's why I also recommended Kerio Connect. Despite which Google Apps is a great product which, if nothing else is making the others sit up and take notice.
Alan Stevens