Ip check using asp net forms authentication


ASP.NET is a popular language used for developing web applications. One common requirement in web development is to perform IP checks using ASP.NET Forms Authentication. In this article, we will explore how to implement IP checks using ASP.NET Forms Authentication with examples.

Step 1: Enable Forms Authentication

we can IP checks, we need to enable Forms Authentication in our ASP.NET application. To do this, we need to add the following code at the beginning of our ASP.NET code:


This code enables Forms Authentication and specifies the login and default URLs for our application.

Step 2: Implement IP Check

Now that we have enabled Forms Authentication, we can proceed to implement the IP check. We can this by creating a authentication that checks the client's IP address before allowing access to the application.

Here is an example of how we can implement the IP check:

    using System;
    using System.Web;

    public class IPCheckModule : IHttpModule
        public void Init(HttpApplication context)
            context.AuthenticateRequest += new EventHandler(context_AuthenticateRequest);

         void context_AuthenticateRequest(object sender, EventArgs e)
            string clientIP = HttpContext.Current..UserHostAddress;

            // Perform IP check logic here
            if (clientIP != "")
                HttpContext.Current.Response.StatusCode = 403;

        public void Dispose()
            // Cleanup code here

In this example, we a custom HTTP module called “IPCheckModule” that implements the “IHttpModule” interface. We subscribe to the “AuthenticateRequest” event and perform the IP check logic in the event handler.

If the client's IP address is not equal to “” (localhost), we set the HTTP status code to 403 (Forbidden) and end the response, effectively denying access to the application.

Step 3: Register the Custom Module


This code registers our custom module with the name “IPCheckModule” and specifies the type as “IPCheckModule”.


In this article, we have explored how to implement IP checks using ASP.NET Forms Authentication. By enabling Forms Authentication, creating a custom authentication module, and registering the module in the application's configuration file, we can effectively perform IP checks and restrict access to our ASP.NET application based on the client's IP address.

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