ARCHIVED: What is NTLM?

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NTLM, a Windows network authentication protocol, is a challenge/response system that allows a client to prove its identity without sending a password to the server. The Windows domain controller challenges the client to perform a complex mathematical calculation on the user's domain password and send this encrypted password to the domain controller. The domain controller then uses the same calculation to decrypt the password. If the decoded password matches the password obtained from the Security Account Manager (SAM) database, then the client is authenticated and may log into the network and access network resources.

NTLM is an abbreviation for Windows NT LAN Manager; it offers improved security over the now-obsolete LAN Manager protocol. The Indiana University network is configured to use only the latest version of this protocol: NTLMv2. This version provides increased security over NTLMv1.

A Real Time Communication (RTC) application may specify RTCAU_NTLM in the tag to indicate the client will accept NTLM authentication challenges.

Some of the information above comes from the Microsoft Development Network library.

This is document atsa in the Knowledge Base.
Last modified on 2018-01-18 15:25:53.