We have a product (Helix Media Library, if you want to know) on a 2008R2 server that uses LDAP authentication of Active Directory members for access. For some reason the LDAP authentication request is only successful against one of our older (2003) Windows Domain Controllers. If that DC is shut down, all authentication fails.
Attached is a config file for an Authorization Test program that we run, at least partially sanitized, that when set to any other DC, still ends up talking with the OLDDC and fails if that DC is down. The log output for a successful and unsuccessful test is also attached.
I can see the 2008R2 server logon entries to other DC's in the Security Event Log of both the sending and receiving server, but it seems like the system keeps going until it gets to the OLDDC before it succeeds or fails.
Any ideas on why this process is "stuck" on the OLDDC and what I can do to un-stick it?