I was recently on the phone with Microsoft support, and they are still very much aware of (and seem to have no plans to fix) the bug in the IIS 7 Manager (Server 2008+) wherein changes at the top “Default Web Site” level tend to propagate to—and overwrite—settings on subfolders: http://briandesmond.com/blog/redirecting-owa-urls-in-exchange-2010/
In more detail, if you decide to use the HTTP Redirect option to redirect the “root” directory to https://owa.customer.com/owa, you will break IIS and OWA unless you then go back and un-check the HTTP Redirect option on the other Exchange virtual directories, including (but not limited to):
(YMMV… these folders are dependent on the version of Exchange)
So, with that glaring bug still present in IIS 7, what’s the Microsoft-approved way to redirect to the /owa Virtual Directory? I’m glad you asked!
1) Log onto your Exchange server that has the CAS (Client Access Server) role
2) Fire up the “Internet Information Services (IIS) Manager”:
3) Expand down the tree until you can highlight “Default Web Site,” then click the “Content View” button:
SIDEBAR: Do NOT rename the “Default Web Site”… things will break until you change it back!
4) Right-click a blank area and choose “Explore” from the menu:
5) Right-click in a blank area in the (by default) C:\inetpub\wwwroot directory and choose “New > Text Document”:
6) Type in the following code (though this is purely cosmetic and strictly unnecessary… the file could be blank and it would still work… it’s just helpful if someone is coming in behind you and doesn’t understand how the redirect is actually working):
<title>Redirecting to /owa...</title>
Redirecting to /owa using a HTTP Redirect added to this index.html document in IIS Manager’s Content View...
7) Save the file as “index.html” (with quotes so that the file extension remains intact) in the (default) C:\inetpub\wwwroot directory:
8) Close notepad and return to IIS Manager
9) Highlight your new “index.html” file (you may have to Refresh the screen before you can see it), then right-click on the file and choose “Switch to Features View”:
10) You’ll now see “index.html” under the “Default Web Site” tree… highlight it and choose “HTTP Redirect” from the right-hand pane:
11) Put in the full URL for OWA (including HTTPS, assuming you have a certificate installed) and check the boxes for “Redirect requests…” and “Only redirect requests…” with a status code of “Found (302)”:
12) Highlight “Default Web Site” and double-click on “Default Document”:
13) Highlight “index.html” and click “Move Up” in the Actions pane until it’s at the top of the list:
14) You’re done! Test it out by going to https://owa.mycompany.com/owa (or whatever your OWA URL is)