Gets the visitors IP address for an ASP.NET address. Will take a proxy address if real visitor IP is not forwarded along by the proxy.

GetVisitorIPAddress.cs

/// <summary>
/// Get the IP address of the current client visiting the website.
/// </summary>
/// <returns>String representing the IP address</returns>
public static string GetVisitorIPAddress()
{
    System.Web.HttpContext context = System.Web.HttpContext.Current;
    string ipAddress = context.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];

    if (!string.IsNullOrEmpty(ipAddress)) {
        string[] addresses = ipAddress.Split(',');
        
        if (addresses.Length != 0) {
            return addresses[0];
        }
    }

    return context.Request.ServerVariables["REMOTE_ADDR"];
}