We outsmarted CSGO cheaters with IdentityLogger

> If a player joins with a different Steam ID but with an IP address that is already banned, the system now re-bans them

This works great until you realize you're punishing innocent players because of CGNAT and IP addresses getting rotated. Cheaters usually know how to get their router to request a new IP address. That IP address then gets assigned to someone else later.

They addressed this in the section entitled "Problematic cases of IP address fingerprinting"

I always found it funny how ip bans seemed to be so popular despite being apparently completely ineffective until I realized this was mostly a US thing. In my country (2 of them that I've lived in, in fact) ISPs always assign the client a dynamic address from their very large pools every time I reconnect. This was as true back in the 28.8kb dial up days as it is in the 10gbit FTTH days we live in. Having a static IP address here has always been a service you have to pay for.

I remember this being hilarious when idiots would ip ban me back on the IRC days: "oh no, I have to press the reconnect button!"