Hi2all!

My question is can I gain that my clients on the network use Internet resources only through web proxy? So, if they don't set in their client programs (IE, Firefox, FTP, etc.) proxy settings, no Internet for them! Help is greatly appreciated.

It is possible to create transparent proxy setup, when all clients are redirected to the proxy.
As well you may block 80 TCP, as all HTTP should go trough proxy (users without proxy configuration will be unable to get HTTP pages).

Thank you sergejs, i will try that, if more questions comes up, will post

But this is only for port 80 (default port for www)
Your clients can run mail, ftp, p2p, ...

then allow only port for proxy server and drop everything else

so they can use ONLY http through proxy you provide (and myabe https if set that in firewall filters to pass through