How to force a web proxy below browser level

Question

I need help in forcing several workstations to use an external web proxy.

I realize I will be asking how to do this the "wrong way" considering that: a) Users are not part of any windows group and are all administrator users. b) I do not have access to the routers so can not force the proxy there.

My challenge is to force all the computers at a workspace to use the business's approved web proxy.

I will eventually get the correct infrastructure established, but for now I just need a quick and dirty solution to force the workstations to use a proxy.

Setting the proxy at browser level is useless as the users can just as easily turn it off.

Of course, as each user practically has an administrator account, they can also undo anything I implement.

But, if it were obscure enough, then it would solve the problem until I get a proper network in place.

I was thinking something along the lines of a registry setting, or script that would force the proxy for all browsers. The users are not the kind that would know the first thing about registry settings but would know how to change their browser settings. However, the only registry settings I have seen are for IE only - workstations use various browsers.

Any ideas?

Answer 1

Since they all have administrator accounts and use a variety of different web browsers I'd say you have two solutions.

Using a PAC file, which allows browsers to automatically locate a configuration file which tells them which proxy to use, although this is still also easily disabled by going into Internet Explorers settings and clicking the "Automatically discover proxy" (or whatever it says).

The other option is to use a transparent proxy, with this everyones internet traffic will be forced through the proxy anyway, basically all this is is the proxy set as the default gateway but with rules to redirect web traffic into the proxy port, but it comes at the disadvantage of not being able to filter HTTPS.