Softwr

Networking · head to head

Nebula vs OPNsense

Nebula logo

Nebula

Networking

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

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: 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.; 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: Nebula covers Certificate carried identity, OPNsense covers Stateful firewall on pf.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Nebula and OPNsense actually diverge.

Attributes where Nebula and OPNsense differ
AttributeNebulaOPNsense
PlatformsLinux, macOS, Windows, iOS, Android, FreeBSDx86-64 appliances, Virtual machines, Deciso hardware

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 Nebula

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

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.

Nebula

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

OPNsense

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

Where each one falls short

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

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.

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

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

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 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

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 Nebula or OPNsense better?
Neither clearly leads. Nebula 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, Nebula or OPNsense?
Nebula starts at Free and OPNsense at Free.
Does Nebula or OPNsense run on more platforms?
Nebula runs on Linux, macOS, Windows, iOS, Android, FreeBSD. OPNsense runs on x86-64 appliances, Virtual machines, Deciso hardware.
Can I use Nebula for free?
Both have a free tier, so you can try either at no cost before committing.
What is Nebula best used for?
Nebula is most often used for flattening a network across several clouds and datacentres without vpc peering or route tables, very large fleets where a central policy service on the connection path is unacceptable, environments that already run an internal certificate authority and want the network to use it, replacing per host iptables rules with policy written against roles that follow the host. Of those, flattening a network across several clouds and datacentres without vpc peering or route tables and very large fleets where a central policy service on the connection path is unacceptable are not what OPNsense is typically brought in for.
What can Nebula do that OPNsense cannot?
Nebula covers Certificate carried identity, Group based host firewall, Lighthouse discovery, Noise protocol encryption. OPNsense covers Stateful firewall on pf, VPN suite, Suricata IDS and IPS, Full configuration API.

Answered from the vendors’ own pages

Nebula: Does it use WireGuard?

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

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.

Nebula: Can I run it without Defined Networking?

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

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.

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.

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.

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.

Share

Related pages

More on Nebula

More on OPNsense

Keep looking

Other head to heads