The single most frequent question I get from people discovering Varnish is "Do you support request collapsing?". And I must admit, it always catches me off guard, because of course, it has been doing so for years, and it's a caching server, so that's a must-have, right? (Yes, yes it is.)

For this reason, in this post, we are going to review some of the little features we take for granted but that also make Varnish a great origin shield.