Microsoft's Exchange Server 5.5 Debuts

My favorite new feature is differential download of the offline address book (OAB). I travel a lot and depend on the OAB when I'm disconnected from the network. I download the OAB often because I need accurate information. In the past, downloading this 55,000-user OAB took many minutes. But with differential download, I now receive only the changes that have occurred since my last download. My telephone bills are much lower!

Interconnectivity: New Connectors
Exchange has always offered a strong lineup of connectors. Microsoft's buyout of LinkAge Software in May further strengthened the lineup because the buyout led to the addition of Lotus Notes, IBM PROFS, and IBM SNADS connectors in Exchange 5.5.

The new connectors will likely satisfy your messaging and communication needs. Interoperability with Lotus Notes is good. You can send rich-text format messages, documents, and other attachments between the two systems without fuss. You can also receive delivery receipts and other status-type messages. Directory synchronization between Exchange and Lotus Notes is relatively straightforward and works much like the synchronization between Exchange and Lotus cc:Mail.

Although the Lotus Notes connector's messaging and communication functions are strong, some restrictions exist. For example, you cannot encrypt messages in either direction and you cannot synchronize Exchange public folders and Lotus Notes databases. (Microsoft will likely close these relatively minor gaps over time.)

You need to install some of the dynamic link libraries (DLLs) that Lotus Notes provides on the server to configure the Lotus Notes connector. But aside from the DLL installation, you can use Exchange 5.5's administration program to manage the connection.

Because Lotus Notes enjoys a high profile in the market, the Lotus Notes connector will likely receive most coverage. However, the PROFS and SNADS connectors are important, too, because they will ease the introduction of Exchange into corporate environments that use PROFS and SNADS email systems. Although PROFS and SNADS email systems are not at the cutting edge, they offer dependable service (albeit at a much-reduced level of functionality compared to Exchange).

The SNADS connector requires Microsoft SNA Server (2.11 or 3.0) and handles the popular SNADS messaging systems, such as Fischer TAO, Soft-Switch Central and Lotus Message Switch, and Software AG CONNECT. Directory synchronization is unavailable for PROFS and SNADS connectors in Exchange 5.5, but I wouldn't be surprised if this feature appeared in the future. PROFS calendaring is also unavailable.

Exchange 5.5 is not ignoring older connectors, either. Spamming and other nefarious acts are a fact of Internet life. You can prevent such acts with the Exchange Internet Mail Service, which lets you control incoming Simple Mail Transfer Protocol (SMTP) connections. For example, you can insist on authenticated incoming SMTP connections for the Internet Mail Service, effectively stopping spammers from sending your users unwanted messages. Screen 3 shows how to set an authenticated connection as properties of the Internet Mail Service.

Exchange 5.5 offers unrivalled connectivity to other messaging systems. The combination of a heavy-duty MTA and a wide set of connectors delivers functionality that major competitors can't match. For example, Exchange 5.5's MTA can increase its capacity to process messages by splitting a single MAPI queue into seven. Splitting queues lets servers process a much greater quantity of mail.

The Lotus Notes connector is available in both editions of Exchange 5.5, but you must buy the Enterprise Edition to get the PROFS or SNADS connectors. (For information about which Exchange edition to use, see the sidebar "Two Editions Are Available," page 170.) The new connectors are available for only Intel systems, but Microsoft promises to release Alpha versions soon, probably in a service pack, in early 1998. The connectors are available only in English, so for French, German, or Japanese versions, you'll have to wait for the service pack.

Clients: Better Support
A 16-bit version of Outlook is available for the first time. In addition, an Apple Macintosh version of Outlook is available to complete the Outlook lineup across client platforms.

Microsoft has upgraded Outlook in many ways. For example, you can now access Schedule+ and Outlook calendars from Web browsers. Outlook also supports deleted-items recovery and HTML forms. You can create and save a form in HTML format, much like what's possible with Word documents. You can also use a wizard to convert existing forms created with earlier versions of Exchange to HTML.

Secure MIME (S/MIME)-capable clients, such as Outlook Express or Netscape Communicator, can send encrypted messages to each other via Exchange 5.5. (Like the other previous clients, IMAP4 clients still need a client access license.) However, Exchange servers don't encrypt or decrypt messages--those tasks are left to the client. You can expect to see S/MIME capabilities in a future release of Outlook, but not when Exchange 5.5 ships.

Exchange 5.5 now supports IMAP4, as Screen 4 shows. This addition is part of Microsoft's continuing effort to have Exchange 5.5 support as many clients as possible.

Enabling Technology: The Exchange Scripting Agent
Exchange 5.5 introduces the Scripting Agent, also known as the Event Service, to invoke processing when changes (called events) occur in folders. If you add, change, or delete items in a folder, the Scripting Agent will trigger an application to run. However, you need to create the code that tells the Scripting Agent which application to trigger. As a result, the Scripting Agent is a diamond in the rough because it needs application developers to take advantage of its capabilities. Even so, the Scripting Agent is already laying a firm foundation for document management and workflow applications in Exchange 5.5. A future issue of Windows NT Magazine will supply more information about the Scripting Agent.

Chat Service
I'm not quite sure how people will use the new Chat Service. An Internet Locator Server supplements the Chat Service, letting users locate people in the Exchange directory and connect to them for an online discussion. Supposedly, you can combine the Chat Service with Microsoft NetMeeting to incorporate online communication into active pages so that companies and their customers can have realtime chats. I'm a little skeptical about the overall usefulness of these features, but I'm happy to wait and see.

Exchange's Journey Is Not Over
Keeping up with Exchange's rapid pace of development can be exhausting at times. Exchange 5.5, with its many new developments, is no exception. Exchange 5.5 now supports all the major Internet protocols, helping it to achieve client universality. You can reasonably argue that Exchange 5.5 is at least as pure an Internet citizen as any of its competitors. In addition, you can use Exchange 5.5's massive information store, two-node cluster support, and deleted-items recovery to build large, cost-effective servers.

But Microsoft will face several challenges in 1998. The next version of Exchange will need to support NT 5.0, which will involve a move toward a unified directory based on the Active Directory. At the same, Exchange will need to support true clustering in MSCS Phase 2 and take advantage of new hardware developments in disk, tape, and CPU. Most important, Microsoft will need to address manageability. Exchange 5.5 provides many administration features and tools for small to midsize deployments but provides relatively few for large implementations. Given the drive and pace behind Exchange, I'll be interested to learn how Microsoft engineers meet these challenges.