What you are learning
Wallspire is host firewall rule labs. The teaching focus is Firewall (iptables, nftables, allow/deny).
Work in order. Early parts set vocabulary and environment; later parts assume the earlier checkpoints.
How to use these lessons
Read the goal, open the matching GitHub folder, complete the lab or exercises, then return for the explanation. If a command fails, check you are in the numbered folder first.
Parts in order
Each chapter below is one checkpoint in this lab.