An IP Gate is an object mentioned in FantendoFall; it is the gate that a User comes from when they register. During the events of FantendoFall, KP Blue blocks every IP preventing registration. Cobweb and Henrydamoose perform a risky plan to temporarily unblock JesseRoo's IP so that he can re-register, as Lopunny. That is the only time an IP Gate is mentioned, as it says Lopunny tumbles through a gate.
All of the IP Gates are found in the Registration Plains. The IP Addresses of Bureaucrats are the closest to Fan City. The Sysop gates are next, and then the regular IP's. Whenever a second account comes from an IP Gate, they are checked to make sure they are not a Sockpuppet.