Delay in getting public IP from my asp.net application

Question

I have an asp.net website in which I am getting the external IP using the below code.

  public static string GetExternalIp() { try { string externalIP = ""; externalIP = (webclient.DownloadString("http://checkip.dyndns.org/")); externalIP = (new Regex(@"\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}")).Matches(externalIP)[0].ToString(); return externalIP; } catch { //return null; return Dns.GetHostByName(Environment.MachineName).AddressList[0].ToString(); } } 

The code is getting the external IP perfectly however, it takes 3 to 5 secs to get the public IP to my application. Based on this stackoverflow post Public IP Address i added the below line to my code as the user has mentioned this will be faster for the consecutive times in getting the public IP

public static WebClient webclient = new WebClient();

However this is also taking time. I googled and found another code using HTTPWebRequest. Below is the code

  string myExternalIP; string strHostName = System.Net.Dns.GetHostName(); string clientIPAddress = System.Net.Dns.GetHostAddresses(strHostName).GetValue(0).ToString(); string clientip = clientIPAddress.ToString(); System.Net.HttpWebRequest request = (System.Net.HttpWebRequest) System.Net.HttpWebRequest.Create("http://www.whatismyip.org"); request.UserAgent = "User-Agent: Mozilla/4.0 (compatible; MSIE" + "6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)"; System.Net.HttpWebResponse response = (System.Net.HttpWebResponse) request.GetResponse(); using(System.IO.StreamReader reader = new StreamReader(response.GetResponseStream())) { myExternalIP = reader.ReadToEnd(); reader.Close(); } 

This code is fast but its creating a html document containing the public IP.

How to get only the IP address from that HTML document?

Is there any code which will be more fast than the one I am currently using.

Answer 1

Use a different service, such as ipify.org with json response. It's faster and requires no parsing.

using Newtonsoft.Json;
using System.Net;

namespace Stackoverflow
{

    public static class GetExternalIP
    {
        class IpAddress
        {
            public string ip { get; set; }
        }
        public static string GetExternalIp()
        {

            WebClient client = new WebClient();

            string jsonData = client.DownloadString("https://api.ipify.org/?format=json");
            IpAddress results = JsonConvert.DeserializeObject<IpAddress>(jsonData);

            string externalIp = results.ip;

            return externalIp;
        }
    }
}