Tony Pompili

Microsoft Exchange Server 5.0 and its newest client, Microsoft Outlook 97, are looking more appealing for companies standardizing on Microsoft Corp.'s 32-bit Windows client and server operating systems. If you don't plan to construct your messaging system around Windows NT Server, though, Exchange will not make the grade. Teamed with Outlook, Exchange offers impressive integrated messaging, calendaring, and information management features. But Exchange isn't planning on getting swallowed up in some proprietary tar pit: This newest version of Exchange is rich with Internet-standard services, including an NNTP newsgroup server, a directory based on the Lightweight Directory Access Protocol (LDAP), and a POP3 mail server.

Part of the Microsoft BackOffice family of products, Exchange Server is tightly integrated into Windows NT Server. Designed as a powerful client/server messaging system, Exchange is Microsoft's core application for providing groupware services for both its proprietary line of clients and its standards-based intranet clients. Based on the Messaging Application Program Interface (MAPI), Exchange Server acts as the message and document storage system for the various new Internet services. Exchange's integration with Windows NT Server makes it simple to manage its NNTP server, LDAP directory, and POP3 server, as well as the new Internet Mail Services SMTP server.

On the client side, the new Outlook client is an attractive replacement for the Exchange client. Microsoft has delivered an easy-to-use interface for managing messaging, public databases, calendaring, and a variety of other tasks. Unfortunately, Outlook runs only under Windows 95 and Windows NT. Microsoft still includes the Exchange client, however, for Windows 3.x and Macintosh users.

Exchange ties neatly into the Windows NT Server architecture. With Exchange installed, you can simultaneously create new Exchange and Windows NT user accounts. Similarly, because Exchange relies on Windows NT's security, users need only log in once to a Windows NT domain to access their Exchange accounts. Exchange shares other Windows NT services, such as the Event Viewer, which allows Exchange to log its errors in a single database with those of other Windows NT applications.

The new Internet services in Exchange 5.0 also take advantage of this intimate relationship with Windows NT. It's a real advantage to have access to the Microsoft Internet Information Server and Windows NT's Domain Name Service (DNS) server, standard applications that ship with Windows NT Server.

As Exchange Server integrates tightly with Windows NT, the new Internet services fit tightly into Exchange's hierarchical database structure. The Exchange directory, for example, includes support for the LDAP directory, allowing any LDAP client to access it. Exchange has one of the most intuitive management architectures of all the products reviewed here. The Exchange Administration Program lets you organize services and users in a single enterprise-wide tree, similar to Novell's hierarchical directory service, NDS. We found this graphical tree structure useful for managing our test servers and more effective than the nonhierarchical name-and-address book design found in Lotus Domino. But, unlike in Domino or SuiteSpot, you cannot manage Exchange via a Web browser.

Exchange's message and data store remains relatively monolithic. The Exchange server stores all the mail folders of a site's users in a single database and all of the public folders in another. Domino, on the other hand, stores each user's mail as a separate file. Right now, Exchange databases can be as large as 16GB each, and Microsoft intends to increase this ceiling, bringing it somewhere close to 16 terabytes by the end of the year.

New to this version is the Outlook client. Shipping with both Exchange Server 5.0 and Microsoft Office 97, Outlook is an integrated messaging, calendaring, contact, and task management application that can operate either standalone or networked. Like the previous Exchange client, Outlook can access a variety of MAPI-based and other mail systems, including CompuServe, Lotus cc:Mail, and Microsoft Mail, though it is clearly tuned for Exchange.

Outlook features an intuitive interface for locating and reusing information. For example, you can use a smartly designed contact form to record a contact's name, address, phone number, and other personal information with the Contact tool. You can drag the contact's name onto the Inbox icon and a new mail message will be created automatically. Outlook's excellent use of drag-and-drop is especially helpful when you are customizing views. By clicking on a column heading, you can reorder, sort, and even categorize views.

Outlook lets users launch a Web page from within its tools. It recognizes URLs in text, and clicking on a link launches your Web browser. Optionally, you can install the ActiveX version of Microsoft Internet Explorer as part of Outlook, giving you the advantage of using Microsoft's popular browser while keeping access to Outlook's menus and tools.

Outlook includes many Exchange-specific components for creating applications. You can now design new forms, such as a customized mail form, within Outlook, rather than using the external Exchange Forms Designer (though that's still an option). The built-in Outlook Forms Designer lets you create and place fields and controls on a grid. Similar to Notes, Exchange Server lets you specify field types, such as numbers, date, or text, and even set rules to validate input. The intuitive designer is especially useful for creating customized mail and discussion applications, and it also lets you customize Outlook's calendar, contact, and other forms.

Outlook uses Microsoft's VBScript, a streamlined version of Visual Basic, for automating forms and creating custom navigation tools. We found that VBScript makes it possible to produce some impressive workgroup applications. Like Notes APIs, MAPI gives developers working with tools such as Visual Basic relatively high-level access to the store, the directory, and other Exchange services.

Microsoft takes big Internet strides with Exchange 5.0, allowing users to access its mail and public folders with Internet-standard clients. Users can send and receive mail with a POP3 client. Exchange can translate its proprietary text formatting into HTML, viewable by POP3 clients that can read HTML (including Netscape's POP3 client and the Microsoft Internet Mail and News client). Users with POP3 clients that don't read HTML, such as Eudora, can disable the feature in order to display plain text. The Exchange NNTP server works similarly with Exchange's public folders, which are NNTP-enabled by default, allowing a user with appropriate privileges to access Exchange discussions with any newsgroup reader.

Beyond simple mail and discussion folders, you can use Microsoft's Active Server Page (ASP) technology to create interactive Web applications for Exchange. ASPs are HTML pages with embedded commands in Microsoft's JScript or any other scripting language. ASPs provide a basic architecture for creating dynamically generated Web applications. They have the ability to call a variety of other applications--such as the new ActiveX Messaging objects, which let developers reach into Exchange's services (including its message store and directory, to retrieve and render information in HTML pages).

Though ASP has promise, it lacks structure and functionality, especially when compared with Lotus Domino, which can render almost any type of database into HTML. Currently, the ActiveX Messaging objects cannot access some Exchange objects, such as calendar documents. For the most part, you're limited to discussions and standard messages. Also, customized forms created in products like Outlook have to be redesigned for HTML with a product like the forthcoming Microsoft Visual InterDev, a toolkit of Web design and management applications.