TL;DR
Install the OPNsense Zabbix Agent plugin → enable it → set Hostname to exactly your Zabbix host name → set Active Check Servers to zabbix.maksonlee.com → in Zabbix, create a host with the same name and link a FreeBSD by Zabbix agent active template → verify in Latest data within ~2 minutes.
Background on why “active” matters: https://www.maksonlee.com/zabbix-agent-active-vs-passive-what-they-mean-and-when-to-use-each/
Tested Environment
- OPNsense 25.7.x
- Zabbix Server 7.4.x
- OPNsense plugin: os-zabbix72-agent
- Install the plugin (GUI)
System → Firmware → Plugins → search zabbix → click + on os-zabbix72-agent to install.
Note: If the Services → Zabbix Agent menu doesn’t appear immediately after install, refresh the page (or reboot once).
- Configure the agent: Main Settings
Services → Zabbix Agent → Settings → Main Settings
Fill exactly:
| Field | Value |
|---|---|
| Enabled | ✓ |
| Hostname | opnsense.maksonlee.com (must match the Zabbix “Host name” exactly; case-sensitive) |
| Listen Port / Listen IPs | leave defaults (Active checks don’t use them) |
| Zabbix Servers | Optional. Set zabbix.maksonlee.com only if your template keeps any passive items; otherwise leave default |
Click Apply.
- Turn on Active checks
Services → Zabbix Agent → Settings → Advanced
Set:
| Field | Value |
|---|---|
| Enable Active Checks | ✓ |
| Active Check Servers | zabbix.maksonlee.com |
| Active Check Refresh | 120 (default is fine) |
| PSK based encryption | Optional; if enabled, configure the same identity/key on the Zabbix host |
Click Apply.
Network note: allow outbound TCP 10051 from OPNsense to your Zabbix. No inbound 10050 rule is required.
- Create the host in Zabbix
Data collection → Hosts → Create host
- Host name:
opnsense.maksonlee.com(exactly the same as in OPNsense) - Interfaces: Optional here; Active checks don’t rely on it
- Templates: link a FreeBSD by Zabbix agent active template
The stock “Template OS FreeBSD by Zabbix agent” is passive. Use an active variant.
Wrap-Up
With Active checks, OPNsense pushes metrics out to Zabbix on TCP 10051, no inbound agent ports on the firewall. Match hostnames, set the Active server to zabbix.maksonlee.com, link a FreeBSD-active template, and you’re done.