How Can I Retrieve My Public IP Address Programmatically?

Accessing Your Public IP Address Programmatically

Determining your router's public IP address programmatically can be tricky. This article explores several methods to achieve this without relying on external services.

C# Implementation (Asynchronous)

This C# example utilizes the HttpClient class and an asynchronous method for efficient IP address retrieval:

using System;
using System.Net.Http;
using System.Threading.Tasks;
using System.Net;

public class ExternalIP
{
    public static async Task<IPAddress> GetExternalIpAddressAsync()
    {
        string externalIpString;
        try
        {
            using (var client = new HttpClient())
            {
                externalIpString = await client.GetStringAsync("http://icanhazip.com");
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error retrieving IP: {ex.Message}");
            return null;
        }

        externalIpString = externalIpString.Replace("\r\n", "").Replace("\n", "").Trim();
        if (IPAddress.TryParse(externalIpString, out var ipAddress))
        {
            return ipAddress;
        }
        return null;
    }

    public static void Main(string[] args)
    {
        Task<IPAddress> externalIpTask = GetExternalIpAddressAsync();
        externalIpTask.Wait();
        IPAddress externalIp = externalIpTask.Result ?? IPAddress.Loopback;

        Console.WriteLine(externalIp);
    }
}

C# Implementation (Using WebClient - Less Preferred)

While functional, the WebClient class is considered obsolete. Here's a simpler example for comparison:

using System;
using System.Net;

public class ExternalIP
{
    public static void Main(string[] args)
    {
        string externalIpString;
        try
        {
            using (var client = new WebClient())
            {
                externalIpString = client.DownloadString("http://icanhazip.com");
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error retrieving IP: {ex.Message}");
            return;
        }

        externalIpString = externalIpString.Replace("\r\n", "").Replace("\n", "").Trim();
        IPAddress externalIp = IPAddress.Parse(externalIpString);

        Console.WriteLine(externalIp);
    }
}

Command-Line Alternatives

For quicker retrieval, consider these command-line options:

• Linux and Windows: wget -qO- http://bot.whatismyipaddress.com
• Using curl: curl http://ipinfo.io/ip

These methods provide various approaches to programmatically obtain your public IP address. The asynchronous HttpClient method is recommended for modern C# development.

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