Hard to lookup, since every second topic here includes firewall or proxy.
I'd like to setup fw rules so only proxy traffic is allowed to go through.
Thanks for cues,miro
Just allow the traffic to your proxy IP and your proxy port. Don't allow any other ports (except for DNS maybe).
Configure your clients to use this proxy --> Done.
If your proxy is in the same subnet like your clients, just allow your proxy ip to connect to 53 (dns), 80 (hhtp), 443 (hhtps) to any.