I need to block internet access for some users on our Windows Servers 2008 R2. If you google this question you will find a lot results that propose to disabling Internet Explorer and setting a proxy to 0.0.0.0. Unfortunately this can easily bypassed using a portable Firefox for example.
Is there a more restrictive solution? I need to find a way that even telnet, ftp etc. won't work.
Thanks for your help!
Update for clarification: I would like to block internet access only for some users, not or all on this server.