Thank you very much @khoesaanie for posting your review, it solved my problem.
Works great 21.2 Cinnamon, apply this if no network interfaces 'sudo chmod +x /usr/bin/dumpcap'
THE network sniffer tool for many years. And yes: old in Mint's app manager, therefore I included the wireshark PPA .
so useful, also really nice way for learning computer networks( just wonder and search )