Open Proxies Scan - is it necessary?
A security scan by P service
All clients are scanned upon connection for open proxies for security reasons. That means that the proxyscan service will try to connect to the user's computer, and if successful, try to connect back to QuakeNet through the proxy. If successful with that, the user gets a temporary ban from QuakeNet. It is up to the user to secure his or her computer. If you get banned, it could also mean that you have a trojan or that you have broken rules of our network.
So if you see a warning from your firewall software saying that 18.104.22.168 (or proxyscan.quakenet.org) is connecting, don't worry, that's just P scanning for open proxies.
If you don't want to be scanned, don't connect to QuakeNet.
Read more about Open Proxies here.