This repository contains a custom Docker build for the OpenThread Border Router (OTBR), which builds with multicast routing disabled.

The primary purpose of this custom build is to disable OPENTHREAD_CONFIG_BACKBONE_ROUTER_MULTICAST_ROUTING_ENABLE. This is necessary for environments where the host kernel does not support multicast routing (e.g., standard Talos Linux kernels), which causes the standard OTBR agent to crash.

To maintain Backbone Router functionality while disabling multicast routing, this build enables OTBR_DUA_ROUTING (Domain Unicast Address ND Proxying) as an alternative.

The Dockerfile:

1. Clones the official openthread/ot-br-posix repository.
2. Patches the CMake configuration to inject:
   • -DOPENTHREAD_CONFIG_BACKBONE_ROUTER_MULTICAST_ROUTING_ENABLE=0
3. Configures the build with:
   • -DOTBR_DUA_ROUTING=ON (Required when multicast routing is disabled)
   • Other standard OTBR flags.

docker build . -t otbr-custom

The repository includes a GitHub Actions workflow that automatically builds and pushes the Docker image to GitHub Container Registry (ghcr.io) on changes to the main branch.

See the original openthread/ot-br-posix license.