Here is the code for displaying the IP Address of your visitor in ASP.NET

Code:
string trueip = string.Empty;
ip = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
if (!string.IsNullOrEmpty(ip))
{
            string[] iprange = ip.Split(',');
            trueip = iprange[0].Trim();
}
else
{
            trueip = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
}
Hope this comes handy