Get public/external IP address?

Question

I cant seem to get or find information on finding my routers public IP? Is this because it cant be done this way and would have to get it from a website?

Answer 1

Most of the answers have mentioned http://checkip.dyndns.org in solution. For us, it didn't worked out well. We have faced Timemouts a lot of time. Its really troubling if your program is dependent on the IP detection.

As a solution, we use the following method in one of our desktop applications:

    // Returns external/public ip
    protected string GetExternalIP()
    {
        try
        {
            using (MyWebClient client = new MyWebClient())
            {
                client.Headers["User-Agent"] =
                "Mozilla/4.0 (Compatible; Windows NT 5.1; MSIE 6.0) " +
                "(compatible; MSIE 6.0; Windows NT 5.1; " +
                ".NET CLR 1.1.4322; .NET CLR 2.0.50727)";

                try
                {
                    byte[] arr = client.DownloadData("http://checkip.amazonaws.com/");

                    string response = System.Text.Encoding.UTF8.GetString(arr);

                    return response.Trim();
                }
                catch (WebException ex)
                {
                    // Reproduce timeout: http://checkip.amazonaws.com:81/

                    // trying with another site
                    try
                    {
                        byte[] arr = client.DownloadData("http://icanhazip.com/");

                        string response = System.Text.Encoding.UTF8.GetString(arr);

                        return response.Trim();
                    }
                    catch (WebException exc)
                    { return "Undefined"; }
                }
            }
        }
        catch (Exception ex)
        {
            // TODO: Log trace
            return "Undefined";
        }
    }

Good part is, both sites return IP in plain format. So string operations are avoided.

To check your logic in catch clause, you can reproduce Timeout by hitting a non available port. eg: http://checkip.amazonaws.com:81/