ASP.NET: get external IP address

Question

I developed site. I need to get IP of site visitors. I try to use Request, but it have only internal IP:

Response.Write(Request.ServerVariables["REMOTE_ADDR"]);

I looked all keys in Server Variables collection - the same result:

foreach (string var in Request.ServerVariables)
{
    Response.Write(Request[var]);
}

How can I get external IP address?

Answer 1

You can use it to get External (public) IP Address..

public static string getExternalIp()
    {
        try
        {
            string externalIP;
            externalIP = (new 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; }
    }

Answer 2

This it part of my implementation for WebTracking. So here you go a snippet for IpAddress retrieval. You can read more about the Server Variables at Wikipedia.

    /// <summary>
    /// Get ip address from request
    /// </summary>
    /// <param name="request"></param>
    /// <returns></returns>
    private string GetIpAddress(HttpRequest request)
    {
        if (request.ServerVariables.IsNull()) return null;

        var _realAddress = request.ServerVariables[@"HTTP_X_FORWARDED_FOR"];
        if (_realAddress.IsNullOrEmpty())
        {
            _realAddress = request.ServerVariables[@"HTTP_FORWARDED"];
        }
        if (_realAddress.IsNullOrEmpty())
        {
            _realAddress = request.ServerVariables[@"REMOTE_ADDR"];
        }

        return _realAddress;
    }