In a few cases, I need to monitor hosts without any possibilities to install OpenVPN and Zabbix agent on it (switchs, routers, wemos, arduinos…).

On the Zabbix Agent

On the Zabbix agent on the same subnet, install fping :

sudo apt-get install fping

Then create a new UserParameter :

sudo vi /etc/zabbix/zabbix_agentd.conf.d/icmp.conf 

And add the following :

Timeout=30
UserParameter=icmp[*],fping -t 300 $1 | grep alive | wc -l

On the Zabbix Server

Then, on the Zabbix server, create a new Item with a nice flexibility :

Then create an associated trigger :

You’re done. Happy monitoring.