using System.Runtime.InteropServices; [DllImport("wininet.dll")] private extern static bool InternetGetConnectedState(out int Description, int ReservedValue); public static bool IsConnectedToInternet() { int Desc; return InternetGetConnectedState(out Desc, 0); } 반환값이 True면 해당 컴퓨터는 인터넷 연결된 겁니다.