how to get client ip in asp.net(c#.Net)

Introduction:

In this article I will explain how to find system or client machine IP address from which user visited the website in asp.net behind proxy in c#.

Description:
  
Now I will explain how to get system or client IP address of machine from which the user visited the website in asp.net in c#. To implement this one write the code as shown below

 

protected void Page_Load(object sender, EventArgs e)

{

string IPAdd = string.Empty;

IPAdd = Request.ServerVariables["HTTP_X_FORWARDED_FOR"];

if (string.IsNullOrEmpty(IPAdd))

IPAdd = Request.ServerVariables["REMOTE_ADDR"];

lblIP.Text = IPAdd;

}

//or
protected void Page_Load(object sender, EventArgs e)

{

IPAddress myIP = IPAddress.Parse(Request.UserHostName);

IPHostEntry GetIPHost = Dns.GetHostEntry(Request.UserHostName);

Response.Write(GetIPHost.HostName);
}

If you observe above code when users behind any proxies or routers the REMOTE_ADDR/Request.UserHostName returns the IP Address of the router and not the client user’s machine. Hence first we need to check HTTP_X_FORWARDED_FOR/Request.UserHostName, since when client user is behind a proxy server his machine’s IP Address the Proxy Server’s IP Address is appended to the client machine’s IP Address.