Here, we're going to use both the newer method, firewall-cmd & ufw, for listing firewall rules, along with the older (but still popular) method, iptables. We're going to go into the basics of other tables within firewalls, and the storage location for rules.
Listing firewall rules on the command line
Getting ready
Connect to your centos1 VM (and ubuntu1, if desired).
Enable and start firewalld for later examples:
$ sudo systemctl enable --now firewalld
How to do it...
While most of this book can be generalized to multiple distributions, firewalls are one...