Using the Nmap to list our opened port in our machine, how described the official website: Nmap “..is an utility for network discovery and security auditing..”
Regarding CUPS from the official website: “is an open source printing system developed by Apple Inc. for macOS® and other UNIX®-like operating systems. CUPS uses the Internet Printing Protocol (IPP) to support printing to local and network printers.”
By default we have the cups service running in the system’s startup we could check out issue the following commands:
$ systemctl status cups
and
$ nmap localhost
To stop the cups service:
$ systemctl stop cups
to diable for the startup system:
$ systemctl disable cups