Imagine the following scenario: You have an web application that delivers data, you have a huge number of requests per second, the data is identical for all users, but you want to limit access to authenticated users. Your back end application is slow and does not cache the created data. You also want to lighten the load on the authentication service. Fixing your back end application or your authentication service unfortunately is not an option. I wanted to solve this problem with Varnish and a VCL only solution, so no inline C or Varnish modules are required for my approach. Continue reading "Caching authenticated downloads with Varnish and VCL"