Re: [squid-users] Transparency and blocking other proxies

ons 2006-04-19 klockan 15:09 -0700 skrev jimmy@emobilenetworks.com:
> Greetings all. So we have transparency working for squid, but is there a way to
> block the user from simply using a different proxy under preferences/etc... in
> the browser settings. For example, if a user suspected that we were using a
> transparent proxy to limit their access, they can have a different proxy setup
> on a remote site and enter that address as the proxy address in their browser.
> I know schools use squid, but how do they or anyone prevent this from
> happening? Thank you.

Why do you want to block the use of other proxies? The answer will
differ slightly depending on what it is you are trying to accomplish.

Usually the environments needing to prevent this doesn't allow any
access to the Internet at all on any port unless via the official
proxies.. this way the users do not have any choice but to use the
proxy.

As long as Internet access is generally allowed there is no reliable
method to block the use of other proxies. You can start building large
access lists blocking access to known proxies, but even that is easily
bypassed.

Regards
Henrik