No. 6 of 26 ·Container Networking Software

Flannel

Windows · Linux · Self-hosted

Freedom report

Two barsScore 6.4

Free tierA free tier is on its own pricing page
Open codeNo open-source code on record
Runs widely2 of 6 device platforms
DocumentedPlans, terms and facts published

Flannel is ranked #6 of 26 in container networking software on Freedom251. It runs on Linux, Self-hosted, Windows. There is a free plan.

Flannel plans and pricing

All plans

Flannel Free Open-source Kubernetes networking project · Apache 2.0 license github.com · 4 Oct 2026

Compared on container networking software

Free plan: Yes
CNI plugin: Yes
Network policies: Yes
Encryption in transit: Yes
Supported platforms: Kubernetes, Docker, Linux, Windows

Best Flannel alternatives

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One bar Canal Free tier No. 1Free6.5 One bar VMware Workstation Pro Free tier No. 2Free6.5 One bar Antrea Free tier No. 3Free6.4 One bar Calico Open Source Free tier No. 4Free6.4 One bar CNI Plugins Free tier No. 5Free6.4 One bar Cilium Free tier No. 7Free6.3

The record

Purpose: Flannel provides a layer 3 network fabric for containers designed for Kubernetes.
How it works: A small flanneld agent on each host allocates that host a subnet lease from a configured address space.
Traffic forwarding: Flannel forwards packets between hosts using backends including VXLAN and cloud integrations.
Backends: Documented backends include VXLAN, host-gw, WireGuard, and UDP; VXLAN is the recommended choice.
Encryption: The WireGuard backend encapsulates and encrypts packets using the in-kernel WireGuard implementation.
Network policy: Flannel does not natively enforce network policies, but its Helm chart can deploy a Kubernetes SIGs network policy controller alongside it.
Integrations: The project lists kube-network-policies, Canal, K3s, and RKE2 as projects that integrate with Flannel.
Datastores: Flannel can store network configuration and subnet allocations in the Kubernetes API or directly in etcd.
Supported environments: The project documents Kubernetes and Docker deployments, with Linux and Windows build instructions.
Notable limitation: The project maintains security fixes for the latest release only; older releases are not actively patched.
Security reporting: The security policy directs vulnerability reports to GitHub private vulnerability reporting and says maintainers acknowledge reports within seven days.
Deployment security: Flannel runs as a privileged daemonset with access to the host network, and its security policy advises following least privilege and keeping it updated.
Support: The project points users to the #k3s channel in Rancher Users Slack, the #flannel-users channel in Calico Users Slack, and GitHub issues for bugs.
Compatibility constraint: The backend documentation says a selected backend should not be changed at runtime.
Price from: Free

Where it ranks on Freedom251

Best Container Networking Software in 2026#6 of 26

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Sources

github.com/flannel-io/flannel· checked 4 Oct 2026
github.com/flannel-io/flannel/blob/master/Document· checked 4 Oct 2026
github.com/flannel-io/flannel/blob/master/Document· checked 4 Oct 2026
github.com/flannel-io/flannel/blob/master/SECURITY· checked 4 Oct 2026