What is LAN Manager authentication level
NTLM is a challenge/response protocol where in the authenticating server or domain controller issues a challenge which the client authenticates using the password hash as a key. NTLM has been repeatedly patched over the years to address security vulnerabilities. The oldest Windows systems can only send back the LM response originally developed in the 80s for LanManager. With NT Microsoft developed a stronger hash and response mechanism called NTLM but continued supporting LM. Vulnerabilities were found in NTLM prompting NTLMv2. For more information on NTLM see “Network security: Do not store LAN Manager hash value on next password change”. These patches affect connectivity to/from older versions of Windows and this setting allows you to tweak NTLM on this computer to be strict and less compatible with older systems or more compatible but less secure. Note that the values for this setting impact how the computer handles NTLM authentication both as a client and as the authentic...