How to restrict access to web pages in the explained matter?

I have a web application developed in pure JSP and Servlet. Application can be deployed local servers and run. Now we have a requirement where we will get a notification as soon as someone deployed the application in their server. The application will send us the IP address of the machine which the application is deployed.

We wrote a ServletContextListener and added the code into it, so it will execute only once in the apps life time.

Now for the above thing, internet connection is must, that is OK. But the issue is the application should not give access to the web pages/ servlets if the notification is not sent to us.

I know this kind of thing can be done in desktop applications, but how to do this in web applications?