There are a few IP address ranges that are reserved for private use. For example,
NetRange: 192.168.0.0 - 192.168.255.255
NetRange: 10.0.0.0 - 10.255.255.255
Another private address range, but less known, is the following:
NetRange: 172.16.0.0 - 172.31.255.255
Part of Docker’s network model is to set up a mini private NAT’d network for the virtual interfaces that are used to give each container its own network device. The 172.17.42.1 address happens to be one of the commonly chosen addresses for the gateway bridge. (this ip is chosen at runtime by the docker daemon). Due to the NATing, it is possible that a gameserver running in docker would see the gateway’s IP instead of the end user’s real IP.
Is this gameserver running in docker?