A friend gave me an interesting task: extract IP TTL values from TCP connections established by a userspace program. This seemingly simple task quickly exploded into an epic Linux system programming hack.
I was asked to debug another weird issue on our network. Apparently every now and then a connection going through CloudFlare would time out with 522 HTTP error. CC BY 2.0 image by Chris Combe 522 error on CloudFlare indicates a connection issue between our edge server and the
Two years ago we blogged about our love of BPF (BSD packet filter) bytecode. CC BY 2.0 image by jim simonson Then we published a set of utilities we are using to generate the BPF rules for our production iptables: the bpftools. Today we are very happy to open
A recent blog post posed the question Why do we use the Linux kernel's TCP stack?. It triggered a very interesting discussion on Hacker News. I've also thought about this question while working at CloudFlare. My experience mostly comes from working with thousands of production machines here and I can
The following is a technical post written by Ian Applegate (@AppealingTea), a member of our Systems Engineering team, on how to optimize the Linux TCP stack for mobile connections. The article was originally published as part of the 2012 Web Performance Calendar. At CloudFlare, we spend a significant amount of