CloudFlare “Interview Questions”
For quite some time we've been grilling our candidates about dirty corners of TCP/IP stack. Every engineer here must prove his/her comprehensive understanding of the full network stack. For example: what are the differences in checksumming algorithms between IPv4 and IPv6 stacks?
I'm joking of course, but in the spirit of the old TCP/IP pub game I want to share some of the amusing TCP/IP quirks I've bumped into over the last few months while working on CloudFlare's automatic attack mitigation systems.
CC BY-SA 2.0 image by Daan Berg
Don't worry if you don't know the correct answer: you may always come up with a funny one!
Some of the questions are fairly obvious, some don't have a direct answer and are supposed to provoke a longer discussion. The goal is to encourage our readers to review the dusty RFCs, get interested in the inner workings of the network stack and generally spread the knowledge about the protocols we rely on so much.
Don't forget to add a comment below if you want to share a response!
You think you know all about TCP/IP? Let's find out.
Archaeology
1) What is the lowest TCP port number?
2) The TCP Continue reading