Automatic user login under NT

Greetings, everyone. I'm new on the list (not so on PHP). I'm stuck with a little problem, I'm trying to implement some PHP pages at work, where ASP is used. The platform is NT 4.0 SP6, with PHP 4.2.1. My problem is that with ASP I can have something like Request.ServerVariables("LOGON_USER"). I've tried using $_SERVER["LOGON_USER"] but to no avail. Curiously, Request.ServerVariables("REMOTE_ADDR") and $_SERVER["REMOTE_ADDR"] work like a charm. How can I obtain the login the user entered when logged to his/her machine? Thanks in advance. -- Un gran saludo/Big regards... Arturo Barajas Sistemas PPG SJR +52 (427) 271-9100, ext. 448