I have an Intranet website, not internet, and whenever I go to
http://mysite
The website accepts my integrated authentication of the logged in user on the computer/client via IE.
if I go to the FQDN
http://mysite.something.com
I get prompted for my username and password.
They're the same and site and web pages. What can I do to make them both accept my credentials from IE/logged in user?
Is the FQDN in IE's "Intranet" security zone? If not you will need to add it in, or add in the *.mydomain.com wildcard.
The "Intranet" zone is inferred if you use just the server name (i.e. there are no dots in your URL), but often the "Internet" zone is used if you use the FQDN.
Windows Integrated Authentication is not automatically used for sites in the "Internet" zone.
http://support.microsoft.com/kb/303650