If you haven’t made the jump to Exchange 2007 yet, now is as good of a time as any. There have been tons of implementations already, a service pack, and several rollups since it was originally released to market… I think it’s safe to say that it’s a stable platform to move to. While you’re at it, go ahead and make the switch to Server 2008 as well. There is one sneaky little snag though, and for some reason mention of it seems to be missing from the Microsoft documentation as well as the other online HowTo’s I’ve thumbed through. If you’re like most cases I’ve been involved in, you’re not going to be installing Exchange 2007 in a completely new-to-Exchange environment. Chances are, this is going to be an upgrade / migration… and that’s where the missing link comes in to play. Have Entourage users? Yeah, this applies to you too.
Let me run this down for you. You’ve got several hundred mailboxes, of which a large majority of the users use webmail at some point in their email experience. Each of those users has conveniently bookmarked your company’s webmail address and it probably looks something like yourdomain.com/exchange… right? By now you’ve read that Exchange 2007 treats the "exchange" virtual directory as a legacy directory and is using "owa" instead for Outlook Web Access. Now we don’t want to have to go through and somehow convince all those users to update their bookmarks after you’ve migrated their mailbox over to the new servers (more importantly field the phone calls from users who didn’t listen the first 6 times you told them). You’ve done your homework and decided that the easiest migration path is to implement a client access server (CAS) separate from the mailbox server so you can take advantage of the auto redirecting (read: users with 2007 mailboxes can still browse to /exchange and CAS will automatically redirect their session to /owa… it’s seamless to them) among other things. Great idea… but it doesn’t work if you follow the directions given by Microsoft. Why? They don’t mention the need to add ASP.net to the web server role on the mailbox server.
So what happens without it? Users with a mailbox on the Exchange 2003 servers can login just fine. Users who have their mailboxes on the Exchange 2007 server and browse directly to the /owa address can login just fine. However, users who have a mailbox on the Exchange 2007 servers and browse /exchange get told their username and password is incorrect. Sound familiar? Oh, and wait a minute… lets not forget about our beloved MAC users. You migrated their mailboxes and now they don’t work either (this, after you spent hours trying to get the certificate installed correctly… don’t worry, I’ll discuss that in an upcoming article). Entourage fires up, appears to connect but never downloads any messages or displays the default (or any other) folders. Turns out that Entourage 2004 and 2008 are both hardcoded to send traffic to that /exchange virtual directory… no matter how you configure the client… and Exchange needs ASP.net to properly handle the DAV request. Neat huh?
Already have Exchange installed? All is not lost. Just simply fire up the Server Manager and add the role service to your web server role… or better yet, from the command prompt type ServerManagerCMD -i Web-ASP-net and hit enter (it’s okay guys… the black screen with white letters won’t hurt you). Reboot the server for good luck (in reality an iisreset will do the job), and you’re off to the races.
– Dan Thompson