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Networking · head to head

Icinga vs OPNsense

Icinga logo

Icinga

Networking

Open source infrastructure monitoring, free at its core, with paid support and modules sold separately by Icinga GmbH

From
Free
Rated
-
Full reviewWebsite
OPNsense logo

OPNsense

Networking

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

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Icinga the free core has no vendor SLA, so production incidents are supported through community channels unless a paid support subscription is purchased; 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.
  • They diverge on capability: Icinga covers Forever Free core, OPNsense covers Stateful firewall on pf.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Icinga and OPNsense actually diverge.

Attributes where Icinga and OPNsense differ
AttributeIcingaOPNsense
Pricing modelOpen source core, with paid repository, module and support subscriptions sold separatelyOpen source, no licence fee
PlatformsLinux, Webx86-64 appliances, Virtual machines, Deciso hardware

Identical on both: starting price (Free), 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 Icinga

  • Forever Free core
  • Clustering and HA
  • Icinga Web and API
  • Enterprise modules (paid)
  • Integration ecosystem

Only in OPNsense

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

What people use each for

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

Icinga

  • An IT team wanting unlimited-scale open source monitoring with no per-host licence fee, running standard Linux distributionsnot OPNsense
  • An organisation on RHEL or SLES that wants officially packaged Icinga builds via the repository subscription rather than building from sourcenot OPNsense
  • A team wanting an SLA-backed vendor support relationship rather than relying on community forums for a production monitoring systemnot OPNsense
  • A company already invested in Prometheus and Grafana wanting to add host and service-level alerting from a compatible open source toolnot OPNsense

OPNsense

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

Where each one falls short

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

Icinga

  • The free core has no vendor SLA, so production incidents are supported through community channels unless a paid support subscription is purchased
  • Repository access for enterprise Linux distributions like RHEL and SLES is not free, so organisations standardised on those distributions face a real recurring cost most open source monitoring buyers do not expect
  • Enterprise modules are gated behind a separate module subscription, so some functionality demonstrated in marketing material is not part of the free core
  • Self-hosting and operating Icinga requires real Linux and monitoring expertise that a commercial SaaS tool would otherwise absorb, so total cost of ownership includes staff time not captured in the licence price
  • Pricing for the paid subscriptions varies by geographic region and is not published as a single global rate card, complicating budgeting for multinational organisations
  • The web interface and configuration language, while capable, are less immediately polished than a fully commercial tool like PRTG, and initial setup takes longer to reach a usable state

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.

Pricing, plan by plan

Icinga

Free
  • IcingaFree
    • Unlimited hosts and services
    • Clustering and API
    • Community support
  • Support Subscription$undefined/year
    • Professional support (8x5 or 24/7)
    • Includes module and repository subscriptions

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

Which should you pick?

Choose Icinga if

  • You need forever free core.
  • You want to start without paying.
  • You work on Linux, Web.
  • You also want clustering and ha.
Icinga review

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

Questions people ask

Is Icinga or OPNsense better?
Neither clearly leads. Icinga starts at Free and OPNsense at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Icinga or OPNsense?
Icinga starts at Free and OPNsense at Free.
Does Icinga or OPNsense run on more platforms?
Icinga runs on Linux, Web. OPNsense runs on x86-64 appliances, Virtual machines, Deciso hardware.
Can I use Icinga for free?
Both have a free tier, so you can try either at no cost before committing.
What is Icinga best used for?
Icinga is most often used for an it team wanting unlimited-scale open source monitoring with no per-host licence fee, running standard linux distributions, an organisation on rhel or sles that wants officially packaged icinga builds via the repository subscription rather than building from source, a team wanting an sla-backed vendor support relationship rather than relying on community forums for a production monitoring system, a company already invested in prometheus and grafana wanting to add host and service-level alerting from a compatible open source tool. Of those, an it team wanting unlimited-scale open source monitoring with no per-host licence fee, running standard linux distributions and an organisation on rhel or sles that wants officially packaged icinga builds via the repository subscription rather than building from source are not what OPNsense is typically brought in for.
What can Icinga do that OPNsense cannot?
Icinga covers Forever Free core, Clustering and HA, Icinga Web and API, Enterprise modules (paid). OPNsense covers Stateful firewall on pf, VPN suite, Suricata IDS and IPS, Full configuration API.

Answered from the vendors’ own pages

Icinga: Is Icinga free to run in production?

Yes, the core platform has no licence fee and no limit on hosts or services monitored.

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.

Icinga: What do the paid subscriptions actually add?

A repository subscription provides packages for certain enterprise Linux distributions, a module subscription unlocks enterprise-only add-on modules, and a support subscription bundles both with professional support.

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.

Icinga: Is Icinga related to Nagios?

Yes, it originated as a fork of Nagios but has since diverged into an independently developed platform.

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.

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