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Networking · head to head

Icinga vs Nebula

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
Nebula logo

Nebula

Networking

Certificate based overlay network from Slack, with identity and firewall rules carried in the certificate

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; Nebula the open source project has no user interface, no enrolment workflow and no revocation service, so certificate issuing, distribution and expiry become scripts you write and then have to keep working.
  • They diverge on capability: Icinga covers Forever Free core, Nebula covers Certificate carried identity.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Icinga and Nebula actually diverge.

Attributes where Icinga and Nebula differ
AttributeIcingaNebula
Pricing modelOpen source core, with paid repository, module and support subscriptions sold separatelyOpen source, no licence fee
PlatformsLinux, WebLinux, macOS, Windows, iOS, Android, FreeBSD

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 Nebula

  • Certificate carried identity
  • Group based host firewall
  • Lighthouse discovery
  • Noise protocol encryption
  • Unsafe routes
  • Managed option

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 Nebula
  • An organisation on RHEL or SLES that wants officially packaged Icinga builds via the repository subscription rather than building from sourcenot Nebula
  • A team wanting an SLA-backed vendor support relationship rather than relying on community forums for a production monitoring systemnot Nebula
  • A company already invested in Prometheus and Grafana wanting to add host and service-level alerting from a compatible open source toolnot Nebula

Nebula

  • Flattening a network across several clouds and datacentres without VPC peering or route tablesnot Icinga
  • Very large fleets where a central policy service on the connection path is unacceptablenot Icinga
  • Environments that already run an internal certificate authority and want the network to use itnot Icinga
  • Replacing per host iptables rules with policy written against roles that follow the hostnot 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

Nebula

  • The open source project has no user interface, no enrolment workflow and no revocation service, so certificate issuing, distribution and expiry become scripts you write and then have to keep working.
  • Revoking a compromised host means distributing a blocklist entry to every other host and reloading them, which is a fleet wide operation rather than a click, and easy to get wrong under pressure.
  • Changing a host group membership means reissuing and redeploying its certificate, so policy changes are a deployment rather than a configuration edit.
  • There is no identity provider integration or single sign on in the open source version, so it maps well to servers and badly to a fleet of user laptops.
  • NAT traversal is best effort and hosts behind symmetric NAT need a relay configured deliberately, so connectivity failures show up as intermittent rather than immediate and are awkward to diagnose.

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

Nebula

Free
  • NebulaFree
    • Full functionality under the MIT licence
    • No host limit
    • You operate the certificate authority and lighthouses
  • Defined Networking$undefined/month
    • Hosted control plane and enrolment
    • Managed certificate lifecycle and revocation
    • Policy and DNS interface

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 Nebula if

  • You need certificate carried identity.
  • You want to start without paying.
  • You work on Linux, macOS, Windows, iOS, Android, FreeBSD.
  • You also want group based host firewall.
Nebula review

Questions people ask

Is Icinga or Nebula better?
Neither clearly leads. Icinga starts at Free and Nebula at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Icinga or Nebula?
Icinga starts at Free and Nebula at Free.
Does Icinga or Nebula run on more platforms?
Icinga runs on Linux, Web. Nebula runs on Linux, macOS, Windows, iOS, Android, FreeBSD.
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 Nebula is typically brought in for.
What can Icinga do that Nebula cannot?
Icinga covers Forever Free core, Clustering and HA, Icinga Web and API, Enterprise modules (paid). Nebula covers Certificate carried identity, Group based host firewall, Lighthouse discovery, Noise protocol encryption.

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.

Nebula: Does it use WireGuard?

No. Nebula predates the common WireGuard mesh tools and uses the Noise protocol framework with its own certificate format.

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.

Nebula: Can I run it without Defined Networking?

Yes, entirely. Defined Networking sells the control plane conveniences, not the network itself.

Icinga: Is Icinga related to Nagios?

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

Nebula: How do I revoke a host?

Add its certificate fingerprint to the blocklist in the configuration of the other hosts and reload them. There is no online revocation check.

Nebula: Is it a good fit for laptops?

Less so than the identity provider based tools. There is no single sign on, so every laptop needs a certificate issued and renewed by whatever process you build.

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