Guillaume Quintard

Recent Posts

Request coalescing and other reasons to use Varnish as origin shield

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.

 

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7/29/20 11:14 AM
by Guillaume Quintard

The best way to completely purge a Varnish cache


It's cargo-cult fighting time! Today, we are going to look at a ban expression that you probably have used, and maybe even have recommended (gasp!) to your fellow Varnish users:

req.url ~ /

We'll discuss why we use it, why it's good but mostly bad, and how to fix it. Hopefully, along the way, we'll shed some light on some Varnish internals that you can use in other situations.

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6/18/20 4:08 PM
by Guillaume Quintard

Web Application Firewall in the Varnish mainline

As you probably know, Varnish has always been a very secure piece of software but so far, that safety only applied to itself and therefore, a malicious request could still go through it and hurt your backend. But as a reverse-proxy (load-balancer, origin shield, etc.), Varnish is going to see everything the backend receives and sends, so there's a great opportunity here to sanitize the traffic before it reaches it.

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7/24/19 3:00 PM
by Guillaume Quintard

novcl: an alternative to VCL

If you've read a few of my blog posts, you probably already know I love the VCL (Varnish Configuration Language) idea, big time. Being able to change the processing logic via code opens a world of possibilities and makes pretty much all other tools feel constrained in their configurations. But...

But, well, VCL is code, and code is scary to a lot of users, and I can understand when you begin with Varnish and only have very limited configuration needs, VCL can feel complicated and some would prefer a simple, declarative language. The good news is that it's totally possible, let's see how we can help!

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2/6/19 1:30 PM
by Guillaume Quintard

Varnish Software Blog

The Varnish blog is where our team writes about all things related to Varnish Cache and Varnish Software...or simply vents.

 

 
 

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