For example, by default we have ICMP Echo request filtered on our servers but ping results are still valid, so I assume it's using another type like most game server lists.
I notice empty game servers will connect to a cloudflare IP on TCP port 80 briefly when starting, then also a German IP 176.9.132.78 and connect on and off to it on random Remote TCP ports such as 45355 48855(Local port is the same as the actual game server listen port).
Game Clients I assume use UDP on the game port to ping each server that reports to the master server IP.
Using MTR or any pinging program will show a consistent network latency that is always slightly and sometimes greatly lower than that listed in the game server list and in game ping list. This can be on an empty server with less than 2% CPU load and replicated from various locations.
