authentification with Internet Explorer

I'm using this code to authenticate users: if (! isset($PHP_AUTH_USER)) { Header("WWW-Authenticate: carga basica=\"Carga de datos\""); Header("HTTP/1.0 401 Unauthorized"); header("Cache-Control: no-cache, must-revalidate"); header("Pragma: no-cache"); echo "No se puede cargar datos si no es un usuario autorizado.\n"; exit; The problem is that IE 4 or 5, does nothing with the headers I send. It just falls to the echo at the end. What can I do? Thanks!!! -- "And I'm happy, because you make me feel good, about me." - Melvin Udall ----------------------------------------------------------------- Martín Marqués email: martin@math.unl.edu.ar Santa Fe - Argentina http://math.unl.edu.ar/~martin/ Administrador de sistemas en math.unl.edu.ar -----------------------------------------------------------------