Microsoft Windows XP [Version 5.1.2600] (C) Copyright 1986-2001 Microsoft Corp. C:\WINDOWS>netsh ras set authmode ?
set authmode [mode = ] STANDARD|NODCC|BYPASS
Sets the mode that determines whether and when dialin clients should
be authenticated.
mode - The mode
STANDARD - All devices need to be authenticated.
NODCC - Direct-connect devices are not authenticated.
BYPASS - Authentication is not required for any device.