A system for setting a router identifier in a network supporting at least one protocol. The system includes an interface storage storing information about at least one port and its Internet protocol address, a router identifier storage storing information about a reference router identifier, an interface manager referring to the interface storage to set information about the Internet protocol address of the port having the highest priority as the reference router identifier, and storing a value of the reference router identifier in the router identifier storage, and at least one daemon process accessing the router identifier storage when automatically setting the router identifier in conjunction with the generation of an event, looking up the value of the reference router identifier, and setting the stored reference router identifier as the router identifier thereof.