Network security: Minimum session security for NTLM SSP based (including secure RPC) clients
This security setting allows a client to require the negotiation of 128-bit encryption and/or NTLMv2 session security. These values are dependent on the LAN Manager Authentication Level security setting value. The options are:
Require NTLMv2 session security: The connection will fail if NTLMv2 protocol is not negotiated.
Require 128-bit encryption: The connection will fail if strong encryption (128-bit) is not negotiated.
Default: No requirements.
Computer Configuration\Windows Settings\Local Policies\Security Options
At least Windows XP SP2, Windows Server 2003