NTLM - The NTLM scheme is a proprietary Microsoft Windows
Authentication protocol (considered to be the most secure among currently supported
authentication schemes).
Note: For NTLM authentication, the user name must be preceded by
the name of the domain it belongs to, as in the following
example:
domain\username
Kerberos - An
authentication protocol that works on the basis of tickets to allow nodes
communicating over a non-secure network to prove their identity to one another in a secure
manner.