Method for detecting gateway in private network and apparatus for executing the method

A gateway detection method of a private network and a gateway detection device are provided to more safely using a device accessible to an external network from the private network. It is decided whether it is possible to access at least two Internet environments(S201). If so, a driving action of a gateway for connection between a private network and an external network is detected(S202). When deciding whether it is possible to access the at least two Internet environments, it is decided whether at least two NICs(Network Interface Cards) are activated. The NICs consist of the first NIC for connection with a private network and the second NIC for connection with an external network.