Posts by Marek Majkowski

We're hosting a Null Singapore meetup!

Published on by Marek Majkowski.

We're happy to announce that next week CloudFlare is hosting the Null Security meetup in Singapore. You are invited! Null is a community for hackers and security enthusiasts. Monthly meetups are organized in a number of Asian cities. Read more at http://null.co.in/. The lineup for the February

The story of one latency spike

Published on by Marek Majkowski.

A customer reported an unusual problem with our CloudFlare CDN: our servers were responding to some HTTP requests slowly. Extremely slowly. 30 seconds slowly. This happened very rarely and wasn't easily reproducible. To make things worse all our usual monitoring hadn't caught the problem. At the application layer everything was

Mobile Ad Networks as DDoS Vectors: A Case Study

Published on by Marek Majkowski.

CloudFlare servers are constantly being targeted by DDoS'es. We see everything from attempted DNS reflection attacks to L7 HTTP floods involving large botnets. Recently an unusual flood caught our attention. A site reliability engineer on call noticed a large number of HTTP requests being issued against one of our customers.

Kernel bypass

Published on by Marek Majkowski.

In two previous posts we've discussed how to receive 1M UDP packets per second and how to reduce the round trip time. We did the experiments on Linux and the performance was very good considering it's a general purpose operating system. Unfortunately the speed of vanilla Linux kernel networking is

How to achieve low latency with 10Gbps Ethernet

Published on by Marek Majkowski.

Good morning! In a recent blog post we explained how to tweak a simple UDP application to maximize throughput. This time we are going to optimize our UDP application for latency. Fighting with latency is a great excuse to discuss modern features of multiqueue NICs. Some of the techniques covered