Not Able to Block Sites On Windows PCs

[rajesh.bahl]

Dear All,

Need your help in resolving an issue.

We have CentOS 4.7 server running okay. One of the applications is Squid Proxy along with Squid Guard. This was working fine until recently  a user installed a software called "Ultrasurf" on windows PC.  That particular PC user can now access all the blocked sites.

I tried to block this user by putting domain name and IP of the server for this application under  "db and urls"  sections under  the "proxy" directory of Squidguard database ( and subsequently creating new .db files ) but the user is still able to access the blocked sites .

Does that mean that we can not block a windows PC user with this software running ?
The squidguard log file shows following messages:-

Warning: Possible byepass attempt.Found multiple slashes where only one is expected : < URL>

Pls. help !



thanking in advance
rajesh.bahl

[Ricky]

Ultrasurf is used to bypass firewall. We can still block this person if we can get to know that on what principle it works ! I have no information about its working as well as their site seems not disclosing their method clearly.