It was common to hear that you can only automate what you do manually, but these days a lot of the underlying tasks have changed. Iptables is an absolute doddle to automate, TBH, and the entire security coverage that Iptables offered has often been superseded by security groups in AWS, sidecar proxies with service meshes, etc, so the whole paradigm has changed. What I meant about the article being quite old, is not just that the solutions are old, but the problems being solved have gone away, or should have. Ok, I did come across a client at the beginning of the year doing it the old way, but they were an Internet Exchange around since 1994, so I understood that.