Q: Which authentication protocol? In the System.DirectoryServices namespace, when using the "Secure" value for the AuthenticationTypes enumeration while instantiating a DirectoryEntry, what authentication protocol is being used?
The following link says NTLM is being used: link text, but does that mean LM, NTLMv1, or NTLMv2?

A: It depends on the OS, and/or the configuration. It will be the most secure NTLM available on the machine. Since NTLMv2 made its debut with Windows NT4, there are very good chances that it will be NTLMv2.

A: NTLMv2, Unless you're using windows 98 or NT. Still, not very secure since it does not use  AES or SHA-256.
