/usr/lib/firewalld/services/ Current File: //usr/lib/firewalld/services/ptp.xml

<?xml version="1.0" encoding="utf-8"?>
<service>
  <short>Precision Time Protocol (PTP) Master</short>
  <description>The Precision Time Protocol (PTP) allows to synchronize computers to a time master. Enable this option, if you are providing a PTP master. You need the linuxptp package installed for this option to be useful.</description>
  <port protocol="udp" port="319"/>
  <port protocol="udp" port="320"/>
</service>