Docker / Networking, Ports & Service Connectivity
Inspect Docker network MTU context during large-transfer failures
An overlay, VPN or host-path MTU mismatch can allow small requests while larger transfers stall. Record network configuration before changing it.
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 network inspect --format '{{json .Options}} {{json .IPAM.Config}}' appnetRead the result
The options can include driver-specific MTU intent; effective interface and path MTU require additional host evidence. A timeout alone does not prove fragmentation trouble.
Resolve and verify
Compare controlled application and packet-size behavior with the supported driver and host network design. Plan one justified managed MTU correction and retest.
Before changing production
Do not globally reduce MTU or reinstall networks based on one failed ping.