public void GetExtIP()
        {
            string myWanIp = "http://www.mywanip.com";
            string strToFind = "\"ipaddress\">";
            string requestLine = "";
            HttpWebResponse response;
            HttpWebRequest request;
            
            try
            {
                request = (HttpWebRequest)WebRequest.Create(myWanIp);               
                request.Method = "GET";
                response = (HttpWebResponse)request.GetResponse();

                StreamReader reader = new StreamReader(response.GetResponseStream());

                while (!reader.EndOfStream)
                {
                    requestLine = reader.ReadLine();
                    if (requestLine.Contains(strToFind))
                    {
                         requestLine = requestLine.Replace("<p class=\"ipaddress\">", "");
                         requestLine = requestLine.Replace("</p>", "");
                         ExtIPTextBox.Text = requestLine;
                         break;
                    }
                 }
                reader.Close();
                response.Close();
            }
            catch (WebException ex)
            {
                MessageBox.Show("Error: " + ex.Message);
                ExtIPTextBox.Text = "Error";
            }
            
        }