There are advantages and disadvantages to spoofing Outlook into using its native protocol to talk to a non-native back end. On the plus side, Outlook-to-Exchange communication via MAPI relies on RPCs (remote procedure calls) as a transport mechanism, increasing the number of packets that need to be exchanged between the client and the server. The increased packet overhead makes the bandwidth for dial-up connections a real bottleneck in the Exchange world. MAPI-connector technology avoids this overhead by converting MAPI to a less-bandwidth-intensive transport on the client before it traverses the network.

On the negative side, MAPI is Microsoft's protocol. It is documented (though not well), and Microsoft remains committed to using it, not only for Outlook but also for the e-mail hooks other Office applications use. Of course, that doesn't mean Microsoft won't pull the rug out from under MAPI or change it enough so that existing products no longer

function as intended. However, because MAPI is embedded in so many Microsoft and third-party applications, this scenario is unlikely, but forewarned is forearmed.

Just the Two of Them

We tested two contestants: Stalker Software's CommuniGate Pro (CGPro) mail server and SuSE Linux's Openexchange Server (SLOX). Because SLOX doesn't yet have a MAPI connector, it lacks several crucial capabilities. For this reason, we tested both products but did not rank the pair against each other. SLOX may be missing a MAPI connector, but it does have Outlook replication technology that works well.

But why is SLOX lacking a MAPI connector? Here's our short tale of woe: SuSE assured us that its MAPI connector would be available in time for our tests. When we installed the product in April, the CD didn't have the connector, but we weren't worried. Toward the end of April, when it still wasn't available, we started to ask our SuSE contacts about it. Finally, after a series of e-mail and voicemail messages that some might term threatening, we got the company's final answer--no connector until late this year! We asked why and were told, "after all, this is open-source code and it's difficult to predict when something will be finished." We hope this doesn't become a common excuse in the open-source community.

And what about the other vendors in this supposedly exploding market? We contacted most of the first- and second-tier mail-server vendors, and even some third tier, to discuss our tests and their plans for moving into the Exchange Server replacement market. Many of these vendors said they are interested in entering the MAPI-connector market but most are still at the planning stage. In particular, keep your eyes on Rockliffe. You should see something from this vendor soon.

Oracle and IBM have MAPI connectors but declined to participate in our tests. Oracle purchased an Outlook connector when it bought Steltor in 2002 and rolled that technology into its Collaboration Suite. The folks at Oracle talked about wanting to compete against Microsoft and IBM-Lotus but, in our opinion, they didn't have a good reason for declining to participate in this review. IBM's Lotus division has a MAPI connector for Domino but the company is in the process of moving the development of this connector in-house. Initially IBM agreed to participate, but later it declined. Ironically, the third-party developer for IBM's old connector was Microsoft.

The SCO Group has a MAPI connector for its SCOoffice Mail Server. SCO suspended shipment of its Linux-based products in May because of its legal battle over Linux. The company contends Linux is an unauthorized derivative of Unix. SCOoffice Mail Server can run on UnixWare 7 with Linux Kernel Personality, but with all the legal maneuvering going on, SCO bypassed the chance to participate in our tests.

Exchange Rate

MAPI Features click to enlarge

Our efforts to get IBM, SCO and Oracle to participate in our tests confirmed one thing: Plenty of Exchange Server replacement products exist, and more are on the way. That means there's money to be made and money to be saved. Software costs, training and platform choice are the key factors for any company considering implementing an Exchange Server replacement. Based on pricing from Microsoft's Web site, a 200- or 1,000-user Exchange 2000 server would cost about $70 per user, assuming you could support 1,000 users on a single Exchange Server and with no volume discount given. SLOX runs about $41 per client for a 260-user groupware server and $33 per client for 1,010 users. CommuniGate Pro's licensing is different, but the savings are even better. A CommuniGate Pro license for 200 groupware clients runs $40 per client, and the license for 1,000 users drops the price per client to $22.

We know the initial purchase price of a product is a small part of the TCO story, but based on our experience with Exchange, CGPro and SLOX, the ongoing management and administration costs for the non-Exchange products would at worst be equal to Exchange. Realistically, we're sure those costs would be less. On the training front, because many corporate users are using Outlook or Outlook Express, retraining them to use Outlook with a third-party Outlook connector is a nonissue. However, it's a huge factor in any integration strategy. And finally, the third-party products provide platform choice. CGPro runs on 28 platforms--including Windows 2003 server--and doesn't force your organization to upgrade to Active Directory to implement the latest release. SLOX runs on SuSE Linux only, so you don't have a choice there unless it's a choice between Exchange on Windows or an Exchange-like product on Linux.

For now, if you're seeking a server with Exchange Server functionality for your Outlook clients you still have a choice. Use Exchange or use Stalker's CGPro. If you need browser-based access to groupware functionality, put SLOX on your list. By year's end, you should have additional Exchange Server replacement products to consider.