If you want to know which ports are open on your Mac, you can use built-in tools in terminal:
lsof -i -P | grep -i "listen"
This gives you a list with all applications and their open ports:
launchd 1 root 7u IPv6 0xddffe8ef3a82ead1 0t0 TCP *:5900 (LISTEN)
launchd 1 root 8u IPv4 0xddffe8ef3a836869 0t0 TCP *:5900 (LISTEN)
launchd 1 root 11u IPv6 0xddffe8ef3a82e4b1 0t0 TCP *:22 (LISTEN)
launchd 1 root 14u IPv6 0xddffe8ef3a82e4b1 0t0 TCP *:22 (LISTEN)
launchd 1 root 18u IPv4 0xddffe8ef3a835ea1 0t0 TCP *:22 (LISTEN)
launchd 1 root 22u IPv4 0xddffe8ef3a835ea1 0t0 TCP *:22 (LISTEN)
launchd 1 root 26u IPv6 0xddffe8ef3a82ead1 0t0 TCP *:5900 (LISTEN)
launchd 1 root 28u IPv4 0xddffe8ef3a836869 0t0 TCP *:5900 (LISTEN)
kdc 182 root 5u IPv6 0xddffe8ef3a82de91 0t0 TCP *:88 (LISTEN)
kdc 182 root 7u IPv4 0xddffe8ef3a837bf9 0t0 TCP *:88 (LISTEN)
rapportd 389 peter 4u IPv4 0xddffe8ef405bfea1 0t0 TCP *:51350 (LISTEN)
rapportd 389 peter 5u IPv6 0xddffe8ef3a82c611 0t0 TCP *:51350 (LISTEN)
ARDAgent 412 peter 9u IPv6 0xddffe8ef3a82f0f1 0t0 TCP *:3283 (LISTEN)
syncthing 484 peter 19u IPv6 0xddffe8ef490b6ff1 0t0 TCP *:22000 (LISTEN)
syncthing 484 peter 25u IPv4 0xddffe8ef4861ace1 0t0 TCP localhost:8384 (LISTEN)
Enpass 513 peter 21u IPv4 0xddffe8ef46e39149 0t0 TCP localhost:10391 (LISTEN)