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Network Protocols Glossary

What is a network protocol? Protocols are the rules of the road for how data exists and moves on the network. They allow many different systems and computers to communicate.

NT Lan Manager (NTLM) Protocol

What is NT Lan Manager (NTLM) Protocol?

NTLM is a suite of authentication protocols developed by Microsoft to verify user identities within a network environment. It is used for authenticating users within a Windows domain.


What is the purpose of NTLM Protocol

NTLM operates on a challenge-response mechanism. When a user attempts to access a resource, the following steps occur:

  1. Negotiation: The client sends a message to the server indicating its capabilities and desired security level.

  2. Challenge: The server responds with a random challenge.

  3. Response: The client computes a response based on the challenge and the user's password hash and sends it back to the server.

  4. Verification: The server verifies the response against its stored hash of the user's password. If the response matches, authentication is successful.

NTLM has known vulnerabilities and is considered less secure than more modern protocols like Kerberos, which is the preferred authentication method in modern windows environments.