Is there a way to tell what nat traversal method succeeded?

I have a managed residential gateway (modem/router) that I do not have login access to so I cannot actually check if it has upnp or nat-pmp enabled. However, I used a project called miniupnpc to list devices in my network that supports upnp and that gateway did not show up in that list.

So I am now curious what other method(s) worked to expose my locally running services to other computers outside my LAN but a part of my virtual zerotier network, be it using hole punching or anything else.

Maybe there is some way to log this to a file etc. Any suggestions would be appreciated.