I recently set up a transparent proxy to filter traffic for selected devices on the network. It works great.
But when you try to access a blacklisted page, the proxy gives this message that says "access denied" and to contact your administrator. Is there a way to customize that page to say something else?
Or even silently redirect any blacklisted page access attempts to another website randomly selected from a list?
This is officially not supported but you can overwrite the files in a /usr/local/etc/squid subdirectory. Keep in mind that those changes may not survive squid updates (not common but may happen)