Docker / Networking, Ports & Service Connectivity
Explain why a container name does not resolve on Docker's default bridge
The legacy default bridge and user-defined bridges have different name-discovery behavior. Inspect the network actually used.
Environment and inputs: Docker Engine · Compose v2 and Buildx where specified; Linux containers unless noted. Verify daemon context, installed feature support and authorized host or Swarm manager access first.
Start with this check
Confirm the environment and replace sample objects, namespaces, images, paths and hosts with approved targets. Share only relevant, sanitized output. Follow the workload owner’s process for changes.
docker container inspect --format '{{json .NetworkSettings.Networks}}' appRead the result
The endpoint map identifies attached networks, not every resolver policy or alias. A network called bridge should not be assumed equivalent to a custom application bridge.
Resolve and verify
Compare the intended name-based communication design with supported network behavior. Move through a reviewed deployment plan to an appropriate managed network where needed.
Before changing production
Do not rely on legacy links or edit hosts files manually as a permanent discovery solution.