Why is Alfresco NOT able to support NTLMv2 with "passthru"? 

: NTLMv2 requires a Windows Server 2008 (or higher) for the repository. 

NTLMv2 prohibits "man-in-the-middle" interceptions. 

NTLMv2 is unsecure and is no longer widely use 

NTLMv2 is not supported on Linux-based systems.