We have some unusual task in our office. There is a list of domains(about 1000 items). When a user from our LAN visits one of this domains, we have to add a small banner to the page he sees. Is it possible to do it with a proxy or some other way? Thanks!
It's fairly easy to do with a content-inspecting proxy (something which can easily be made transparent).
However you can't rely on the banner being seen as there's a whole bunch of weird CSS/JS things the web site could be doing.
Straight blocking might be a better idea.