Linux vacca.o2switch.net 4.18.0-553.123.2.lve.el8.x86_64 #1 SMP Thu May 7 23:17:13 UTC 2026 x86_64

//lib/firewalld/services/mqtt-tls.xml

 <?xml version="1.0" encoding="utf-8"?>
<service>
  <short>mqtt-tls</short>
  <description>The Message Queuing Telemetry Transport (MQTT) is a machine-to-machine connectivity protocol. This variant of the protocol uses TLS encryption.</description>
  <port port="8883" protocol="tcp"/>
</service>