Outlook Web Access -- has anyone ever installed it without something going wrong? If the number of OWA questions that we receive is any indication, then the answer is an emphatic NO. In this two-part article, SearchWin2000.com's resident Exchange expert Scott Schnoll answers some of the more frequently asked user-submitted OWA installation questions. May other IT pros' problems become your solutions.
SearchWin2000.com: How do I configure OWA 5.5 with Exchange 2000? I know it's possible, but I don't have any idea how to do it.
Schnoll: It's true -- you can use OWA 5.5 against an Exchange 2000 computer. This is documented in a couple places, including Microsoft Knowledge Base article Q260832. There really isn't much to configure either -- however, there are some caveats.
First, you'll need to install a new Exchange 5.5 SP4 server in your Exchange 2000 site. If you've already converted your Exchange organization to native mode, you won't be able to do this. If you're still in mixed mode, the Exchange 5.5/OWA server will join the Exchange organization. Then users can point to the OWA interface and, once authenticated, their Exchange 2000 mailboxes will be exposed.
Keep in mind that OWA 5.5 uses MAPI and could cause bottlenecks. OWA 2000 no longer uses MAPI and can scale much better. Also keep in mind that you don't need a front-end/back-end configuration in order to use OWA. OWA is installed by default on all Exchange 2000 computers. So if all you need is OWA 2000, then you already have it. Users can simply point their Web browsers to their existing Exchange 2000 server and use all of the new OWA 2000 functionality.
SearchWin2000.com: I have installed everything -- IIS 4.0, Exchange 5.5 and OWA. What is the next step to make sure everything will work?
Schnoll: Once you've completed the install, the next step is to check the event logs for any errors or warnings. If you don't find any, test the site by pointing a Web browser to http://server/exchange where server is the name of your OWA server. You should get a logon page, and once you successfully log on, you'll get your mailbox.
SearchWin2000.com: I have seen that it is possible to use OWA 5.5 SP4 with Exchange 2000 in native mode. I want to get this configuration up and running due to issues we are having with OWA 2000 and our firewall. Can you point me in the right directions for installation instructions?
Schnoll: The instructions are basically the same for OWA to an Exchange 5.5 mailbox computer. These instructions can be found in KB article Q259240. The only difference in your environment is that your users will be accessing an Exchange 2000 server instead of an Exchange 5.5 server.
SearchWin2000.com: I am running an OWA 5.5 with extensive customizations. Can I upgrade to OWA 2000 and preserve my customizations?
Schnoll: Unfortunately, no. OWA 2000 is very different from OWA 5.5. This means that your customizations will be lost as a result of the upgrade. To recreate them, you're going to have to do a little more work. Specifically, you'll need to download the Exchange 2000 SDK and learn how to use Web Store forms.
SearchWin2000.com: Is it possible to install OWA 5.5 and OWA 2000 on the same box?
Schnoll: No, you cannot have both versions running on the same system for the simple reason that you cannot have both version of Exchange on the same system. In Exchange 2000, OWA is part of Exchange; there is no option to NOT install it. Once you install Exchange 2000 on top of Exchange 5.5, OWA 5.5 is completely replaced with OWA 2000. Therefore, you are going to need a second OWA server if you plan on using both versions.
When using OWA in Exchange 2000 and Exchange 5.5 environments, keep the following in mind: you can only use OWA 2000 to access Exchange 2000 mailboxes. You cannot use OWA 2000 to access Exchange 5.5 mailboxes. OWA 2000 is tightly integrated with Exchange 2000, making this impossible. You can use OWA 5.5 with both Exchange 5.5 and Exchange 2000 mailboxes. This is documented in KB article Q260832, among other places.