When attempting to connect to OWA via mail.mydomain.com from the internet I am receiving the following:
Error code: 403 forbidden. The server denied the specific uniform resource locator.
I have this set as a published rule in ISA server 2006. Since I am receiving the 403 error I am going to assume this is some sort of an authentication issue.
Under the listener tab > properties, I have the authentication mode set to HTML for authentication and windows (active directory)
Now on the authentication delegation tab, I have it set to "no delegation, but client may authenticate directly"
On the exchange server, the CAS is set to basic authentication.