HI, Can any one help me please. I have just set up a Windows 2000 domain, which includes two member servers, one being an NT4 Server box, and the other being a WIndows 2000 box. On the 2000 member server, i have ISA server installed (with websense) and on the NT4 server i have WEBsweeper installed. My problem is that i am trying to use pass-through authetication, from the ISA-Server to the WEBsweeper server, but the ISA server does not seem to pass the users credentials on, (even though both servers can see the domain user accounts) and i am being asked to authenticate twice. I have checked that i am using IE5.5 spk2, but still the problem persists. Does anybody know if ISA server can pass-through authenication to WEBsweeper, or is this an issue with mixing NT4 with Windows 2000? Please help.....