By default XOA is firewalled, with only ports 22, 80 and 443 opened. You can see the current status of the firewall using the sudo ufw status verbose command:
Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing)
New profiles: skip
To Action From
-- ------ ----
22 ALLOW IN Anywhere
80 ALLOW IN Anywhere
443 ALLOW IN Anywhere
22/tcp LIMIT IN Anywhere
22 ALLOW IN Anywhere (v6)
80 ALLOW IN Anywhere (v6)
443 ALLOW IN Anywhere (v6)
22/tcp LIMIT IN Anywhere (v6)
If you want to open or close ports, please check the documentation of UFW.