How can I monitor the iptables service on a firewall server from a Zabbix server

[mandla]

Good Day,

I want to add an item on the Zabbix server to monitor the iptables running on my firewall server. I have tried using the service item as follows:
net.tcp.service[tcp,172.16.4.161]

And when I test the config it throws an error saying "invalid third parameter", the third parameter requires a port number and I do not know the port number for iptables.

Is there another way of monitoring the iptables?

Thank you in advance