good netstat options
netstat shows you which ports are open on your linux machine. Most of the
time I simply want to see which ports are open and what process opened them
and this is how I do it:
# install netstat if not installed already
sudo apt install net-tools
# run netstat as root so it can display more info about processes
sudo netstat -tulpn
I heard there's a more modern replacement for this, but I my days only got so many hours.
resources: