I have a linux server acting as gateway and Squid Proxy.
If a client has correctly configured its browser to user proxy at myserverip port 3128 he needs to fill authentication: no problem.
However if he disables proxy in his internet explorer he can surf without authenticatin.
Which is the correct way to force users to authenticate and how can I implement it (Debian)?
Block port 80?
Redirect port 80 traffic to 3128?
How can I achieve this?