Port Scan in Terminal (macOS ver. 11.0.1)

Everything in network utility just used the underlying Unix commands.

here are some ways to do it. Netcat should be part of the default commands, but I think you would need to install nmap if you want to use that.

https://linuxize.com/post/check-open-ports-linux/

Netcat in Big Sur is named nc(1), and netmap.org last compiled the downloadable nmap-7.9.1.dmg installer in Oct. 2020. The installer tosses it into the /usr/local tree. I chose not to install it. The nmap feature is not installed by macOS.