[C#] 判断IP端口是否开启

 static bool IsPortOpen(string host, int port)
{
  try
  {
    IPAddress ipAddress = GetIpAddress(host);
    if (ipAddress == null)
    {
      return false;
    }
    IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);
    using Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
    socket.Connect(remoteEP);
    return true;
  }
  catch
  {
    return false;
  }
}
static IPAddress GetIpAddress(string host)
{
  try
  {
    IPAddress[] addressList = Dns.GetHostEntry(host).AddressList;
    foreach (IPAddress iPAddress in addressList)
    {
      if (iPAddress.AddressFamily == AddressFamily.InterNetwork)
      {
        return iPAddress;
      }
    }
    return null;
  }
  catch
  {
    return null;
  }
}

telnet 10.168.1.100 80