One of Microsoft Exchange 2000 Server's most-touted features is Outlook Web Access (OWA). In fact, many organizations are motivated to upgrade to Exchange 2000 predominantly because of OWA's enhancements. Exchange 5.5 Server's OWA was less than pretty, but Exchange 2000 takes OWA to a new level of functionality. In addition, OWA implementers can improve upon the default feature set and customize it to their specific deployment requirements.

Exchange 2000 OWA is substantially different from the version introduced in Exchange 5.0. OWA in Exchange 5.5 and Exchange 5.0 used Active Server Pages (ASP) to communicate with the server running Exchange. The ASP application used Collaboration Data Objects (CDO) 1.2 and Messaging API (MAPI). Exchange 2000 OWA no longer uses ASP or interpreted scripts for client access and doesn't use MAPI to communicate with the mailbox store. OWA is now built into the Exchange store and uses Microsoft IIS to receive requests and send responses. This core integration with IIS and the ability to directly use Web-based Distributed Authoring and Versioning (WebDAV), an extension to the HTTP/1.1 protocol, opens Exchange 2000 OWA to virtually any degree of customization.

The key to customizing Exchange 2000 OWA is understanding the default core OWA components that you can manipulate. These components are the Tool Bars (the Browser Tool Bar and the OWA Tool Bar), the Content Pane, the Preview Pane, and the Shortcuts Bar. You can change the look and function of each of these components to serve your specific deployment needs. Suppose you want to make OWA available to a user group, but you only want the group members to have access to an Inbox. You can modify OWA's presentation to these users so that they only see an inbox when they log on; the calendar and other Exchange folders won't be visible. Furthermore, Exchange 2000's core functionality and accessibility changes let you use a URL to access most items in the Exchange store (e.g., the navigation bar, folder contents, or individual messages). You can also include URL parameters with the URLs. These parameters are commands (what to do) and their options (how to do it).

If you're looking for ways to add OWA value for your business, don't accept OWA's default implementation. With Exchange 2000, you can manipulate OWA to create an Exchange interface for almost any requirement. If you want more information about customizing Exchange 2000 OWA, Microsoft released a white paper last month called "Customizing Microsoft Outlook Web Access."