The value of the parameter (a string) is the highest protocol level that will be supported by the server. Possible values are : LANMAN1: First modern version of the protocol. Long filename support. LANMAN2: Updates to Lanman1 protocol. NT1: Current up to date version of the protocol. Used by Windows NT. Known as CIFS. SMB2: Re-implementation of the SMB protocol. Used by Windows Vista and later versions of Windows. SMB2 has sub protocols available. SMB2_02: The earliest SMB2 version. SMB2_10: Windows 7 SMB2 version. By default SMB2 selects the SMB2_10 variant. SMB3: The same as SMB2. Used by Windows 8. SMB3 has sub protocols available. SMB3_00: Windows 8 SMB3 version. SMB3_02: Windows 8.1 SMB3 version. SMB3_11: Windows 10 SMB3 version. By default SMB3 selects the SMB3_11 variant. Normally this option should not be set as the automatic negotiation phase in the SMB protocol takes care of choosing the appropriate protocol. server min protocol max protocol protocol SMB3 LANMAN1