NexaYori Tools Open port checkHelp
Open port check

Tests whether TCP ports on 216.73.216.220 (your IPv4 address) accept connections from the internet.

TCP only. UDP services (WireGuard, most game servers, DNS) can’t be tested this way. Only your own address is ever checked, and up to 20 ports at a time.
On IPv4 this tests your router’s public address, so “open” means a port forward is working.
From a terminal: curl "https://tools.nexayori.com/ports?p=22,443"