Microsoft Windows [Version 6.0.6001] (C) Copyright 2006 Microsoft Corp. c:\windows>netsh ras diagnostics set loglevel ?
set loglevel [events=] error | warn | all | none
Sets the global Log level for Routing and Remote Access Service
events - Events to log into the System Log in Event Viewer
none - Specifies that no event is logged
error - Specifies that only errors are logged
warn - Specifies that errors and warnings are logged
all - Specifies to log all events.