What I wish to do happens when the consumer enter in the following: DomainUserName Password

I'm able to the validate when the user and password applies or otherwise, Domain could be LDAP/AD or machine, all of the sample code I'm able to find are validating against AD, which isn't too appropriate during my scenario, any help could be appreciate.

Many thank

This describes how you could do this it insNet3.5

http://msdn.microsoft.com/en-us/magazine/cc135979.aspx#S9