Whenever a browser sends a request for a page, it also sends a number of other headers to the script, containing information such as the browser type. It also includes information such as the visitors IP address.
In ASP.NET you can get the IP address of your users from the Request.ServerVariables collection. The following ASP.NET code will display the visitor’s IP:
<%Response.Write(Request.ServerVariables[“REMOTE_ADDR”]);%>