Dear Developpers and Community, I would like to set up the following configuration using squid: When a user asks for a web page he is transparently redirected to squid, where an authentication must be done before serving the user with content. However, users IP are being NATed before going to the proxy. So the solution would be to use an application-layer verification: cookies or http headers So, I come across the following solutions: 1. Use an ICAP server which checks if a cookie is set, otherwise set it for an authenticated user the problem is: cookies are bound to domains + each http request must be validated 2. Use a php splash page which sets the cookie then redirect to destination same problem as ICAP 3. using squid authentication and checking if Proxy-Authorization header is set before serving the client problem: sessions are associated to the IP by squid I'm using squid 3.1 Thank you for any idea