How block Proxy software with PFsense squid3-dev

[noor]

Dear All,

I am using PFSense with Squid3-dev and Squidguard and i have blocked maximum sites from the Console but i am monitoring that users accessing maximum sites through proxy software and proxy web sites.

how i can blocked All proxy sites what is the Good solution

[KOM]

1.  Educate your users on what is acceptable and punish the users who don't comply with your policy
2.  Block these proxy sites one by one as you discover them.

That's about all you can do.