HookConnect

From RO Wiki

HookConnect was a tool which was used primarily by Japanese Ragnarok Online private servers to connect to private server instances. Rather than modifying the Ragnarok Online client, the HookConnect intercepts connections to a given IP address and reroutes traffic to another IP address. In the case of reverse engineering and private servers, Japanese players would place the official server IP in the HookConnect configuration and redirect to a server running on localhost or other IP address.