Adding my vote for Zabbix. It was a bit of a bear to set up and I had to write custom scripts to install the agents with TLS settings that were secure enough for me, but once it’s all set up it’s amazingly easy and intuitive to use and incredibly customizable.
This is the answer. Although you may need to look up the IP address (a lot of them use 192.168.100.1) and you may need to reconfigure your gateway/firewall/router to route that subnet out its WAN interface while still performing NAT.
Adding my vote for Zabbix. It was a bit of a bear to set up and I had to write custom scripts to install the agents with TLS settings that were secure enough for me, but once it’s all set up it’s amazingly easy and intuitive to use and incredibly customizable.