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Networking · head to head

OPNsense vs Zabbix

OPNsense logo

OPNsense

Networking

FreeBSD-based firewall and routing platform with weekly updates and a full configuration API

From
Free
Rated
-
Full reviewWebsite
Zabbix logo

Zabbix

Networking

Open source infrastructure and network monitoring with distributed proxies and templating

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: OPNsense throughput depends entirely on hardware you selected yourself, and intrusion prevention at multi-gigabit rates will saturate a machine that handled plain firewalling fine, with no vendor sizing commitment to fall back on.; Zabbix the database is the scaling limit, and high frequency polling grows history tables fast enough that untuned installations hit housekeeping stalls and query timeouts within months.
  • They diverge on capability: OPNsense covers Stateful firewall on pf, Zabbix covers Agent and agentless collection.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which OPNsense and Zabbix actually diverge.

Attributes where OPNsense and Zabbix differ
AttributeOPNsenseZabbix
Platformsx86-64 appliances, Virtual machines, Deciso hardwareLinux, Docker, Kubernetes, Web

Identical on both: starting price (Free), pricing model (Open source, no licence fee), free tier (Yes), user rating (Not yet rated), category (Networking).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in OPNsense

  • Stateful firewall on pf
  • VPN suite
  • Suricata IDS and IPS
  • Full configuration API
  • High availability
  • Weekly update cadence

Only in Zabbix

  • Agent and agentless collection
  • Templates
  • Low-level discovery
  • Distributed proxies
  • Trigger expressions
  • Escalation actions

What people use each for

The jobs each tool is most often brought in to do.

OPNsense

  • Replacing a small business firewall appliance whose renewal quote exceeded the cost of the hardwarenot Zabbix
  • Branch offices where the firewall configuration must be produced by Ansible rather than by handnot Zabbix
  • Sites that need WireGuard and intrusion prevention on the same box without separate feature licencesnot Zabbix
  • A homelab or lab network needing VLAN routing, multi-WAN and DNS filtering on one machinenot Zabbix

Zabbix

  • A service provider monitoring thousands of customer devices where per-device commercial licensing is the largest line itemnot OPNsense
  • Branch or industrial sites with unreliable links that need local collection and bufferingnot OPNsense
  • Mixed estates where the same tool must poll SNMP switches, Linux hosts, Windows servers and Java applicationsnot OPNsense
  • Replacing an aging Nagios installation while keeping script-based checks that already existnot OPNsense

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

OPNsense

  • Throughput depends entirely on hardware you selected yourself, and intrusion prevention at multi-gigabit rates will saturate a machine that handled plain firewalling fine, with no vendor sizing commitment to fall back on.
  • The weekly update cadence is good for security but means more change events than a team used to annual appliance firmware, and occasional regressions reach production installations.
  • FreeBSD underneath limits driver support compared with Linux, so recent network cards and some virtualisation drivers can be unsupported or slow.
  • The plugin ecosystem is uneven in quality; some plugins are maintained by a single contributor and can lag a major release, breaking a function you depended on.
  • Community support is a forum, so an outage at two in the morning on the free edition is your problem alone unless you bought the business subscription in advance.

Zabbix

  • The database is the scaling limit, and high frequency polling grows history tables fast enough that untuned installations hit housekeeping stalls and query timeouts within months.
  • Initial configuration is heavy; getting useful alerting rather than noise requires understanding trigger expressions, macros and template inheritance, which is a multi-week learning curve for a team new to it.
  • The AGPLv3 change at version 7.0 affects anyone offering Zabbix over a network as part of a commercial service, and that obligation is easy to inherit accidentally during an upgrade.
  • The web interface is functional rather than pleasant, and many sites end up running Grafana alongside it purely for presentation, which is a second system to maintain.
  • Upgrades between major versions touch the database schema and can take hours on large history tables, so the maintenance window is proportional to how much data you kept.

Pricing, plan by plan

OPNsense

Free
  • OPNsense Community EditionFree
    • MIT licence with no feature restrictions
    • All VPN, IDS and HA features included
    • Weekly updates and two major releases a year
  • OPNsense Business Edition$undefined/year
    • Stabilised update track lagging community releases
    • Commercial support from Deciso
    • Additional enterprise plugins and configuration backup

Zabbix

Free
  • ZabbixFree
    • No device, node or metric limits
    • Full feature set with no paid edition of the software
    • AGPLv3 from version 7.0 onward
  • Zabbix Technical Support$undefined/year
    • Tiered subscriptions with defined response times
    • Access to Zabbix engineers for configuration and performance issues
    • Bug fix priority and backports

Which should you pick?

Choose OPNsense if

  • You need stateful firewall on pf.
  • You want to start without paying.
  • You work on x86-64 appliances, Virtual machines, Deciso hardware.
  • You also want vpn suite.
OPNsense review

Choose Zabbix if

  • You need agent and agentless collection.
  • You want to start without paying.
  • You work on Linux, Docker, Kubernetes, Web.
  • You also want templates.
Zabbix review

Questions people ask

Is OPNsense or Zabbix better?
Neither clearly leads. OPNsense starts at Free and Zabbix at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, OPNsense or Zabbix?
OPNsense starts at Free and Zabbix at Free.
Does OPNsense or Zabbix run on more platforms?
OPNsense runs on x86-64 appliances, Virtual machines, Deciso hardware. Zabbix runs on Linux, Docker, Kubernetes, Web.
Can I use OPNsense for free?
Both have a free tier, so you can try either at no cost before committing.
What is OPNsense best used for?
OPNsense is most often used for replacing a small business firewall appliance whose renewal quote exceeded the cost of the hardware, branch offices where the firewall configuration must be produced by ansible rather than by hand, sites that need wireguard and intrusion prevention on the same box without separate feature licences, a homelab or lab network needing vlan routing, multi-wan and dns filtering on one machine. Of those, replacing a small business firewall appliance whose renewal quote exceeded the cost of the hardware and branch offices where the firewall configuration must be produced by ansible rather than by hand are not what Zabbix is typically brought in for.
What can OPNsense do that Zabbix cannot?
OPNsense covers Stateful firewall on pf, VPN suite, Suricata IDS and IPS, Full configuration API. Zabbix covers Agent and agentless collection, Templates, Low-level discovery, Distributed proxies.

Answered from the vendors’ own pages

OPNsense: How is it different from pfSense?

It is a 2015 fork with an MIT licence, a fixed weekly release cadence, a complete configuration API and a different interface. Feature coverage is comparable; the release process and API are the real differences.

Zabbix: Is Zabbix genuinely free for commercial use?

The software has no licence fee at any scale. From version 7.0 it is AGPLv3, so offering it as a network service to third parties carries source distribution obligations.

OPNsense: Do I need the Business Edition?

Only if you want commercial support or a slower, stabilised update stream. No features are withheld from the community edition.

Zabbix: What is the real cost of running it?

Database administration and the person who tunes it. Budget for PostgreSQL with TimescaleDB and someone who owns the retention policy.

OPNsense: Can it handle a gigabit internet connection?

Plain firewalling on modest current hardware, comfortably. With Suricata inspection enabled, expect to need a considerably stronger CPU.

Zabbix: How does it compare to a commercial per-device tool?

It removes the licence line entirely and adds an operations line. Below a few hundred devices the commercial tool is often cheaper in total; above that Zabbix wins clearly.

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