Nebulavs
Tailscale
Tailscale: If you want single sign on and a managed control plane rather than running a certificate authority
Nebula
Certificate based overlay network from Slack, with identity and firewall rules carried in the certificate
As of 31 August 2026, Nebula is free to use. An overlay network where every host carries a signed certificate that states its identity and its groups, and the firewall rules are evaluated against those groups rather than addresses. Softwr lists it under Networking. Nebula is made by Defined Networking (Nebula maintainers), available on Linux, macOS, Windows, iOS.
Overview
What Nebula does
Nebula is an open source overlay networking tool originally built at Slack and released under the MIT licence. Each host runs a lightweight agent and holds a certificate signed by a certificate authority you control, which carries its overlay IP address, its name and its group memberships. Lighthouse hosts help peers discover each other and coordinate UDP hole punching, and encryption uses the Noise protocol framework rather than WireGuard. The distinguishing design is that identity and policy travel with the certificate. A host firewall rule can say that anything in the group ssh-admins may reach port 22 on anything in the group prod, and that decision is made locally on each host from cryptographic identity rather than from a central policy service that must be reachable at connection time. That is what lets it scale to very large fleets with a control plane that does almost nothing, and it is why it was built at a company with that problem. Buyers are infrastructure teams comfortable with certificate authorities who want a flat encrypted network across clouds and datacentres. The commercial fork in the road is Defined Networking, founded by the Nebula authors, which sells a managed control plane with enrolment, certificate lifecycle, DNS and a policy interface; self hosting gives you the same data plane but leaves certificate issuing, distribution and revocation as scripts you write and maintain yourself.
What people use it 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
Related searches
The honest half
Where it falls short
Concrete and checkable, so you can decide whether any of them matter to you. This is the half of a review a vendor will not write about 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.
Cross-shopped
What people choose instead of Nebula
Each pairing was judged by two reviewers asking whether a buyer would genuinely weigh the two against each other. The ones that failed were deleted rather than published.
- NebulavsNetBird
NetBird: Open source with a self hostable control plane and identity provider integration built in
- NebulavsWireGuard
WireGuard: If the network is small enough that a handful of static peer configurations is simpler than a certificate authority
Pricing
What Nebula costs
Taken from the vendor's own pricing page. Prices move, so check before you buy.
Nebula
Free
- Full functionality under the MIT licence
- No host limit
- You operate the certificate authority and lighthouses
- Community support
Defined Networking
On request
- Hosted control plane and enrolment
- Managed certificate lifecycle and revocation
- Policy and DNS interface
- Vendor support
Capabilities
Features
Certificate carried identity
Each host certificate encodes its overlay address, name and group memberships
Group based host firewall
Rules are written against certificate groups rather than IP ranges, and enforced on each host
Lighthouse discovery
Designated hosts help peers find each other and coordinate NAT traversal
Noise protocol encryption
Uses the Noise framework for the encrypted tunnels between peers
Unsafe routes
Reaches devices that cannot run the agent by routing through a peer that can
Managed option
Defined Networking sells a hosted control plane for enrolment and certificate lifecycle
Answered, with sources
Questions people ask
Each answer names the page it came from, so you can check it rather than take our word for it.
Does it use WireGuard?
No. Nebula predates the common WireGuard mesh tools and uses the Noise protocol framework with its own certificate format.
Can I run it without Defined Networking?
Yes, entirely. Defined Networking sells the control plane conveniences, not the network itself.
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.
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.
Keep looking
Where to go from Nebula
- Nebula alternativesEvery product people weigh against it
- Nebula pricingPlans, floors and what the tiers exclude
- Nebula badgesWhich rules it meets, and the figure behind each
- All Networking softwareThe full category
- Best Networking softwareThe shortlist, and how it was cut
Best Networking software for
Compare Nebula with
- NetBird
- Tailscale
- pfSense
- Icinga
- Zabbix
- Consul
- LibreNMS
- OpenVPN
- Headscale
- Traefik
- Eclipse Mosquitto
- Cisco Meraki
- Domotz
- HiveMQ
- Netdata
- OPNsense
- Zabbix
- Headscale
Other Networking software
Open source WireGuard mesh VPN with identity based access policies and a hosted control plane
Free plan12 researched notesZero-trust mesh VPN built on WireGuard with identity-based access
Free plan12 researched notesOpen source firewall software with a free Community Edition and a separate commercial Plus edition sold by Netgate
Open source12 researched notesOpen source infrastructure monitoring, free at its core, with paid support and modules sold separately by Icinga GmbH
Open source11 researched notesOpen source infrastructure and network monitoring with distributed proxies and templating
Open source10 researched notesFree, community-driven network monitoring with commercial support sold by a third-party partner, not the project itself
Open source11 researched notesOpen source VPN protocol with a commercial Access Server product priced per simultaneous connection
Open source12 researched notesOpen source reimplementation of the Tailscale coordination server for a single organisation
Open source12 researched notesSmall, EPL-licensed MQTT broker that runs on hardware other brokers cannot
Open source12 researched notesCloud-managed networking hardware where the licence is mandatory and the hardware stops passing traffic if it lapses
Pricing on request12 researched notesNetwork monitoring for MSPs and IT teams priced per managed device or per collector, with published rates
12 researched notesEnterprise MQTT broker for industrial IoT with a published self-managed price list
Free, then $299/mo12 researched notesPer-second metrics collection with automatic dashboards and on-node anomaly detection
Open source9 researched notesFreeBSD-based firewall and routing platform with weekly updates and a full configuration API
Open source10 researched notesOpen source infrastructure and network monitoring with distributed proxies and templating
Open source10 researched notesOpen source reimplementation of the Tailscale coordination server for a single organisation
Open source12 researched notes
Softwr does not host reviews and shows no star rating for Nebula, because a rating we did not collect is not ours to publish. What is here is the pricing and platform detail from the vendor’s own pages, limitations we could state concretely, and alternatives a reviewer confirmed people weigh against it. Tell us if any of it is wrong.
More on Nebula
Nebula alternatives
What people switch to, and what they give up
Nebula pricing
Every tier, and where the cost actually lands
Compare Nebula
Put it head to head with anything we hold
Nebula badge
Its rating, and an embed for your own site
Best Networking software alternatives
Open source infrastructure monitoring, free at its core, with paid support and modules sold separately by Icinga GmbH
Open source core, with paid repository, module and support subscriptions sold separatelyNetwork monitoring for MSPs and IT teams priced per managed device or per collector, with published rates
Per collector or per managed device per month
AI-driven wireless and wired networking where a Wi-Fi Assurance subscription is a required, not optional, add-on
quote, hardware plus required Wi-Fi Assurance subscriptionFree, community-driven network monitoring with commercial support sold by a third-party partner, not the project itself
Open source, no licence fee; commercial support sold by a third-party partner
Internet and digital experience monitoring, with a genuinely published entry price through its WebPageTest product line
Free tier plus published entry tiers, enterprise quote-only
Network observability platform built on flow and traffic data, sold on annual-only contracts starting around $24,000/year
Annual contract only, per tierCloud-managed networking hardware where the licence is mandatory and the hardware stops passing traffic if it lapses
quote, hardware plus mandatory recurring licence
Cloud-based network monitoring and management priced by managed device count, quote-only
quote, per managed device