In this article I will explain with an example, how to get Client IP Address of Visitor’s Machine in ASP.Net using C# and VB.Net.
This article will explain, how to get IP Address of Visitors (Client) Machines which don’t use Proxy Servers and also which are behind Proxy Servers in ASP.Net using C# and VB.Net.
 
 
HTML Markup
The HTML Markup consists of:
Label – For displaying client IP Address.
<h1><asp:Label runat="server" ID="lblIpAddress"></asp:Label></h1>
 
 
Displaying IP Address of Visitors Machine in ASP.Net
Inside the Page Load event handler, first the IP Address is determined for the Client machine’s which are behind Routers or Proxy Servers and hence, the HTTP_X_FORWARDED_FOR server variable is checked.
Note: When the Client machine is behind a Proxy Server its IP Address of the Proxy Server is appended to the Client machine’s IP Address.
If there are multiple Proxy Servers then the IP Addresses of all the Proxy Servers are appended to the client machine IP Address.
 
If the IP Address is not found in the HTTP_X_FORWARDED_FOR server variable, it means that, it is not using any Proxy Server and hence, the IP Address is now checked in the REMOTE_ADDR server variable.
Note: While running this application on your machine locally i.e. in Visual Studio, the IP Address will show as 127.0.0.1 or ::1.
This happens because in such case the Client and Server both are the same machine.
Thus, no need to worry when you deploy it on a Server, you will see the results.
 
Finally, the IP Address is displayed using the Label control.
C#
protected void Page_Load(object sender, EventArgs e)
{
    string ipAddress = Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
    if (string.IsNullOrEmpty(ipaddress))
    {
        ipAddress = Request.ServerVariables["REMOTE_ADDR"];
    }
    lblIpAddress.Text = "Your IP Address: " + ipAddress;
}
 
VB.Net
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    Dim ipAddress As String = Request.ServerVariables("HTTP_X_FORWARDED_FOR")
    If String.IsNullOrEmpty(ipaddress) Then
        ipAddress = Request.ServerVariables("REMOTE_ADDR")
    End If
    lblIpAddress.Text = "Your IP Address: " & ipAddress
End Sub
 
 
Screenshot
How to get IP Address of Visitors Machine in ASP.Net
 
 
Demo
 
 
Downloads