In Ubuntu the firewall is managed by UFW. The rules can be manually added or an application configuration file can be added to simplify the process.

I've attached a file with the default ports to simplify firewall setup on Ubuntu.

To use run these commands cp turnserver /etc/ufw/applications.d/turnserver ufw add turnserver

This file should probably be automatically copied as part of the Ubuntu package install (not quite sure how to do this but it's a standard practise).

Fixed in 4.2.2.2