Don’t have things set up at home and need to probe an open port from inside a network? Try out portquiz.net which listens on all TCP ports.

Need something to probe an external port (maybe because you can’t hairpin to the external interface on your firewall)? Try out www.t1shopper.com/tools/port-scan/.

I have no affiliation with these, nor do I attest to their legitimacy. Just tools available out on the web. I use these to test out logs/firewalls.