Code from redrouteone on zabbix share.
Imported to Zabbix 5.4 and translated to English.
In case of getting the error message Cannot find host interface on "Sonicwall" for item key "ifInOctets.0" you have to first add a SNMP interface on your host:
Configuration -> Hosts -> Click on your SonicWall Host -> On the default tab (Host) go to "Interfaces" -> Add -> SNMP -> Input IP Addr or DNS name