I'm attempting to authorize access to a third party program by checking their credentials against Active Directory using NTLM.
This solution has been working for a long time - as it a rolled out product for 5+ years. I have it working on our main domain (of which I am not an administrator) and on a Virtual Machine which is a domain controller running on Server 2008.
I am only having issues on my Server 2003 virtual machine (domain controller) where instead of logging on it responds with this "The authentication mechanism is unknown" error message.
I have no problem authenticating with NTLM from the local machine when I use my test tool which utilizes the same code, the issue seems to be only from outside the PC.
I am using the same machine to connect to all these servers, which is not on any domain (and should not be) as it's a scanner.
I am certain that this has to be a configuration issue with my Server 2003 machine but I have been unable to find out what the cause is. My searching online has revealed very little related information and nothing useful as of yet.
I have tested it with the Windows Firewall turned off and with the Windows Firewall service disabled.
Just ensured that NTLM was enabled in the domain security settings (although I've never had to do this before) by giving
Lan Manager Authentication to allow to send
LM & NTLM responses as described at this webpage. Unfortunately the issue still persists.