Comp 343-001 Week 12 notes

Nov 18

Cloudflare was having problems this morning; in particular, the site challenges.cloudflare.com was down. This is the site that implements Turnstyle, which, when you try to visit a Cloudflare-protected site, sends you some javascript queries which try to determine if  you're a human, using a real browser, rather than a bot.

Cloudflare's primary function is to sit between site webservers and customers. This allows Cloudflare to:

  1. serve up all the static content of the webserver from Cloudflare, offloading the work and allowing the content to be served from the closest Cloudflare datacenter
  2. protect the webserver from mass network attacks (TCP SYN flooding, etc), by dynamically blocking traffic sources sending malicious traffic

Demo of competition

Single-packet losses

Geographical IP routing

BGP