How to get the public IP address of a user in C#

I want the public IP address of the client who is using my website. The code below is showing the local IP in the LAN, but I want the public IP of the client.

//get mac address
NetworkInterface[] nics = NetworkInterface.GetAllNetworkInterfaces();
String sMacAddress = string.Empty;
foreach (NetworkInterface adapter in nics)
{
    if (sMacAddress == String.Empty)// only return MAC Address from first card  
    {
        IPInterfaceProperties properties = adapter.GetIPProperties();
        sMacAddress = adapter.GetPhysicalAddress().ToString();
    }
}
// To Get IP Address


string IPHost = Dns.GetHostName();
string IP = Dns.GetHostByName(IPHost).AddressList[0].ToString();

Output:

Ip Address : 192.168.1.7

Please help me to get the public IP address.

This is what I use:

protected void GetUser_IP()
{
    string VisitorsIPAddr = string.Empty;
    if (HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] != null)
    {
        VisitorsIPAddr = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"].ToString();
    }
    else if (HttpContext.Current.Request.UserHostAddress.Length != 0)
    {
        VisitorsIPAddr = HttpContext.Current.Request.UserHostAddress;
    }
    uip.Text = "Your IP is: " + VisitorsIPAddr;
}

"uip" is the name of the label in the aspx page that shows the user IP.

You can use "HTTP_X_FORWARDED_FOR" or "REMOTE_ADDR" header attribute.

Refer method GetVisitorIPAddress from Machine Syntax blog .

    /// <summary>
    /// method to get Client ip address
    /// </summary>
    /// <param name="GetLan"> set to true if want to get local(LAN) Connected ip address</param>
    /// <returns></returns>
    public static string GetVisitorIPAddress(bool GetLan = false)
    {
        string visitorIPAddress = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];

        if (String.IsNullOrEmpty(visitorIPAddress))
            visitorIPAddress = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];

        if (string.IsNullOrEmpty(visitorIPAddress))
            visitorIPAddress = HttpContext.Current.Request.UserHostAddress;

        if (string.IsNullOrEmpty(visitorIPAddress) || visitorIPAddress.Trim() == "::1")
        {
            GetLan = true;
            visitorIPAddress = string.Empty;
        }

        if (GetLan && string.IsNullOrEmpty(visitorIPAddress))
        {
                //This is for Local(LAN) Connected ID Address
                string stringHostName = Dns.GetHostName();
                //Get Ip Host Entry
                IPHostEntry ipHostEntries = Dns.GetHostEntry(stringHostName);
                //Get Ip Address From The Ip Host Entry Address List
                IPAddress[] arrIpAddress = ipHostEntries.AddressList;

                try
                {
                    visitorIPAddress = arrIpAddress[arrIpAddress.Length - 2].ToString();
                }
                catch
                {
                    try
                    {
                        visitorIPAddress = arrIpAddress[0].ToString();
                    }
                    catch
                    {
                        try
                        {
                            arrIpAddress = Dns.GetHostAddresses(stringHostName);
                            visitorIPAddress = arrIpAddress[0].ToString();
                        }
                        catch
                        {
                            visitorIPAddress = "127.0.0.1";
                        }
                    }
                }

        }


        return visitorIPAddress;
    }

Combination of all of these suggestions, and the reasons behind them. Feel free to add more test cases too. If getting the client IP is of utmost importance, than you might wan to get all of theses are run some comparisons on which result might be more accurate.

Simple check of all suggestions in this thread plus some of my own code...

    using System.IO;
    using System.Net;

    public string GetUserIP()
    {
        string strIP = String.Empty;
        HttpRequest httpReq = HttpContext.Current.Request;

        //test for non-standard proxy server designations of client's IP
        if (httpReq.ServerVariables["HTTP_CLIENT_IP"] != null)
        {
            strIP = httpReq.ServerVariables["HTTP_CLIENT_IP"].ToString();
        }
        else if (httpReq.ServerVariables["HTTP_X_FORWARDED_FOR"] != null)
        {
            strIP = httpReq.ServerVariables["HTTP_X_FORWARDED_FOR"].ToString();
        }
        //test for host address reported by the server
        else if
        (
            //if exists
            (httpReq.UserHostAddress.Length != 0)
            &&
            //and if not localhost IPV6 or localhost name
            ((httpReq.UserHostAddress != "::1") || (httpReq.UserHostAddress != "localhost"))
        )
        {
            strIP = httpReq.UserHostAddress;
        }
        //finally, if all else fails, get the IP from a web scrape of another server
        else
        {
            WebRequest request = WebRequest.Create("http://checkip.dyndns.org/");
            using (WebResponse response = request.GetResponse())
            using (StreamReader sr = new StreamReader(response.GetResponseStream()))
            {
                strIP = sr.ReadToEnd();
            }
            //scrape ip from the html
            int i1 = strIP.IndexOf("Address: ") + 9;
            int i2 = strIP.LastIndexOf("</body>");
            strIP = strIP.Substring(i1, i2 - i1);
        }
        return strIP;
    }

That code gets you the IP address of your server not the address of the client who is accessing your website. Use the HttpContext.Current.Request.UserHostAddress property to the client's IP address.

For Web Applications ( ASP.NET MVC and WebForm )

/// <summary>
/// Get current user ip address.
/// </summary>
/// <returns>The IP Address</returns>
public static string GetUserIPAddress()
{
    var context = System.Web.HttpContext.Current;
    string ip = String.Empty;

    if (context.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] != null)
        ip = context.Request.ServerVariables["HTTP_X_FORWARDED_FOR"].ToString();
    else if (!String.IsNullOrWhiteSpace(context.Request.UserHostAddress))
        ip = context.Request.UserHostAddress;

    if (ip == "::1")
        ip = "127.0.0.1";

    return ip;
}

For Windows Applications ( Windows Form, Console, Windows Service , ... )

    static void Main(string[] args)
    {
        HTTPGet req = new HTTPGet();
        req.Request("http://checkip.dyndns.org");
        string[] a = req.ResponseBody.Split(':');
        string a2 = a[1].Substring(1);
        string[] a3=a2.Split('<');
        string a4 = a3[0];
        Console.WriteLine(a4);
        Console.ReadLine();
    }