If you are worried about the recent cups issue … this is not the lowest hanging fruit. Nor the most effective remediation.
Even skipping to the point of ‘block udp port 631’ - I also echo other sentiments that you dont require a GUI or extra manual service for this. Set rules and enable firewall. It will start early enough.
Since it seems you need assistance with these basic tasks, and might even benefit from some further education … I’ll just leave a friendly reminder that being kind goes a long way. Others might be more willing to hold your hand if you arent snarky or rude.
I know its not always easy to remember but its all people behind these text boxes. Mostly. I think we have at least one hobbit.
PS.
In relation to the recent security scare … this thread may be helpful: