Check if a port is open

Question

I can\'t seem to find anything that tells me if a port in my router is open or not. Is this even possible?

The code I have right now doesn\'t really seem to work...<

Answer 1

public string GetAvailablePort()
        {int startingPort=1000;
            string portnumberinformation = string.Empty;
            IPEndPoint[] endPoints;
            List portArray = new List();
            IPGlobalPr`enter code here`operties properties = IPGlobalProperties.GetIPGlobalProperties();`enter code here`


            //getting active tcp listners 
            endPoints = properties.GetActiveTcpListeners();
            portArray.AddRange(from n in endPoints
                               where n.Port >= startingPort
                               select n.Port);    

            portArray.Sort();

            for (int i = 0; i < portArray.Count; i++)
            {
                if (check condition)
                {
                    do somting
                }
            }

            return portnumberinformation;
        }