Iptables Basics


Yesterday I tweeted “hey, I learned some stuff about iptables today”! A few people replied “oh no, I’m sorry”. iptables has kind of a reputation for being hard to understand (and I’ve also found it intimidating) so I wanted to write down a few things I learned about iptables in the last few days. I don’t like being scared of things and understanding a few of the basics of iptables seems like it shouldn’t be scary!

I have been looking at Kubernetes things, and Kubernetes creates 5 bajillion iptables rules, so it has been time to learn a little bit about iptables.

The best references I’ve found for understanding iptables so far have been:

  • the iptables man page
  • iptables.info (which is GREAT, it explains all kinds of stuff like “what does MASQUERADE even mean” that is not explained in the iptables man page)

Read more at Julia Evans