Ports possibly not exposed in 4.42.0

[jbxonline]

Description

Had one of my devs report that he was getting a 404 on his local dev environment. It looked like the standard 404 page that Traefik serves if it can't find the service it's supposed to be routing to. Looking in the traefik logs, he had this line:

2025-06-05T16:56:56Z ERR github.com/traefik/traefik/v3/pkg/provider/docker/config.go:82 > 
error="service \"php-local\" error: port is missing" 
container=php-local-e202e95115b39285efa98f61a93bdb351455a4a64c6867471805009424b75883 
providerName=docker

It was working for me. So I went through his Docker settings and discovered he was running a slightly newer version of Docker Desktop (both of us on Mac M1 Apple Silicon). So I updated my version of Docker and boom, mine broke too. Reverting back solves the issue.

So this affects several different images that were all running fine behind Traefik on v4.41. Images all expose a port. I have also tried adding an expose: - "8080" in the docker-compose.yml file, but that hasn't helped. Same error.

Any ideas? Thanks in advance.
Jon

Reproduce

docker-compose.yml:

services:
  traefik:
    image: traefik:v3.4
    command:
      - "--log.level=DEBUG"
      - "--api.insecure=true"
      - "--providers.docker=true"
      - "--providers.docker.exposedbydefault=false"
      - "--providers.file.directory=/etc/traefik/dynamic"
      - "--providers.file.watch=true"
      - "--entrypoints.web.address=:80"
      - "--entrypoints.websecure.address=:443"
    ports:
      - "8080:8080"
      - "80:80"
      - "443:443"
  phpmyadmin:
    image: phpmyadmin
    expose:
      - "8080"
    env_file:
      - ./secrets/db_secrets.env
    labels:
      - "traefik.enable=true"
      - "traefik.http.routers.phpmyadmin.rule=Host(`mysql.local`)"
      - "traefik.http.routers.phpmyadmin.entrypoints=web"

docker-compose up -d

Expected behavior

Traefik should find and route traffic to the phpmyadmin container for mysql.local

docker version

Client:
 Version:           28.2.2
 API version:       1.50
 Go version:        go1.24.3
 Git commit:        e6534b4
 Built:             Fri May 30 12:07:35 2025
 OS/Arch:           darwin/arm64
 Context:           desktop-linux

Server: Docker Desktop 4.42.0 (195023)
 Engine:
  Version:          28.2.2
  API version:      1.50 (minimum version 1.24)
  Go version:       go1.24.3
  Git commit:       45873be
  Built:            Fri May 30 12:07:27 2025
  OS/Arch:          linux/arm64
  Experimental:     false
 containerd:
  Version:          1.7.27
  GitCommit:        05044ec0a9a75232cad458027ca83437aae3f4da
 runc:
  Version:          1.2.5
  GitCommit:        v1.2.5-0-g59923ef
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

docker info

Client:
 Version:    28.2.2
 Context:    desktop-linux
 Debug Mode: false
 Plugins:
  ai: Docker AI Agent - Ask Gordon (Docker Inc.)
    Version:  v1.4.0
    Path:     /Users/jon/.docker/cli-plugins/docker-ai
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.24.0-desktop.2
    Path:     /Users/jon/.docker/cli-plugins/docker-buildx
  cloud: Docker Cloud (Docker Inc.)
    Version:  v0.3.9
    Path:     /Users/jon/.docker/cli-plugins/docker-cloud
  compose: Docker Compose (Docker Inc.)
    Version:  v2.36.2-desktop.1
    Path:     /Users/jon/.docker/cli-plugins/docker-compose
  debug: Get a shell into any image or container (Docker Inc.)
    Version:  0.0.41
    Path:     /Users/jon/.docker/cli-plugins/docker-debug
  desktop: Docker Desktop commands (Docker Inc.)
    Version:  v0.1.9
    Path:     /Users/jon/.docker/cli-plugins/docker-desktop
  extension: Manages Docker extensions (Docker Inc.)
    Version:  v0.2.29
    Path:     /Users/jon/.docker/cli-plugins/docker-extension
  init: Creates Docker-related starter files for your project (Docker Inc.)
    Version:  v1.4.0
    Path:     /Users/jon/.docker/cli-plugins/docker-init
  mcp: Docker MCP Plugin (Docker Inc.)
    Version:  dev
    Path:     /Users/jon/.docker/cli-plugins/docker-mcp
  model: Docker Model Runner (Docker Inc.)
    Version:  v0.1.24
    Path:     /Users/jon/.docker/cli-plugins/docker-model
  sbom: View the packaged-based Software Bill Of Materials (SBOM) for an image (Anchore Inc.)
    Version:  0.6.0
    Path:     /Users/jon/.docker/cli-plugins/docker-sbom
  scout: Docker Scout (Docker Inc.)
    Version:  v1.18.1
    Path:     /Users/jon/.docker/cli-plugins/docker-scout
WARNING: Plugin "/Users/jon/.docker/cli-plugins/docker-dev" is not valid: failed to fetch metadata: fork/exec /Users/jon/.docker/cli-plugins/docker-dev: no such file or directory

Server:
 Containers: 8
  Running: 7
  Paused: 0
  Stopped: 1
 Images: 19
 Server Version: 28.2.2
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Using metacopy: false
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Cgroup Version: 2
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local splunk syslog
 CDI spec directories:
  /etc/cdi
  /var/run/cdi
 Discovered Devices:
  cdi: docker.com/gpu=webgpu
 Swarm: inactive
 Runtimes: runc io.containerd.runc.v2
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 05044ec0a9a75232cad458027ca83437aae3f4da
 runc version: v1.2.5-0-g59923ef
 init version: de40ad0
 Security Options:
  seccomp
   Profile: builtin
  cgroupns
 Kernel Version: 6.10.14-linuxkit
 Operating System: Docker Desktop
 OSType: linux
 Architecture: aarch64
 CPUs: 10
 Total Memory: 31.29GiB
 Name: docker-desktop
 ID: 1e3c2eee-82bb-4df3-b319-cdff21608c57
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 HTTP Proxy: http.docker.internal:3128
 HTTPS Proxy: http.docker.internal:3128
 No Proxy: hubproxy.docker.internal
 Labels:
  com.docker.desktop.address=unix:///Users/jon/Library/Containers/com.docker.docker/Data/docker-cli.sock
 Experimental: false
 Insecure Registries:
  hubproxy.docker.internal:5555
  ::1/128
  127.0.0.0/8
 Live Restore Enabled: false

WARNING: DOCKER_INSECURE_NO_IPTABLES_RAW is set

Diagnostics ID

1FB09648-C8C1-40C6-98E5-5925CA678508/20250605181251

Additional Info

No response

[mrleblanc101]

We've been debugging this all morning and came to the same conclusion !
After upgrading to 4.42 on a MacBook Pro M1.
Reverting to 4.41.2 solve the issue for now.

Some container seem to work like maildev, but all our other containers do not and gives 404 using Traefik.

[thomas-lepage]

We currently have the exact same problem.

Docker engine 28.2.X seems to be the problem. 28.1.X is ok. We tried to add the expose in docker-compose like OP, but doesn't change anything. We have confirm that the problem seems to be only present on Mac, some of our linux developer doesn't have the problem.

In 28.1.X docker inspect solr | jq '.[].NetworkSettings.Ports' return

{
  "8983/tcp": null
}

In 28.2.X the same command return:

{}

If we publish the port with -p with a docker run, everything seems to be ok.

[BenjaminYong]

We use the GoLang Docker client and experienced the same issue with the Docker Desktop v4.42.0 update.

To fix it, we made changes to the HostIP to remove the standalone colon :
And removed /tcp suffix from the HostPort

Example 1.

HostPortBindings: nat.PortMap{nat.Port("3939/tcp"): []nat.PortBinding{{HostIP: ":", HostPort: "3939/tcp"}}}

->

HostPortBindings: nat.PortMap{nat.Port("3939/tcp"): []nat.PortBinding{{HostIP: "", HostPort: "3939"}}}

Example 2.

HostPortBindings: nat.Port("3883/tcp"): []nat.PortBinding{{HostIP: "0.0.0.0", HostPort: "3883/tcp"}}}

->

HostPortBindings: nat.PortMap{nat.Port("3883/tcp"): []nat.PortBinding{{HostIP: "0.0.0.0", HostPort: "3883"}}}

Strangely, Docker Desktop doesn't display ports of containers started using Docker CLI or programatically:

Looks to be part of this change:
https://docs.docker.com/desktop/release-notes/#:~:text=Changed%20the%20way%20ports%20are%20mapped%20by%20Docker%20Desktop%20to%20fully%20support%20IPv6%20ports.

[Lordroran]

It seems that windows is affected as well.

[jbxonline]

Looks like this is primarily being tracked here: testcontainers/testcontainers-node#818

[djs55]

Thanks for the reports. I've found a race in the port setup code and made a potential fix. If you'd like to try a test build it's here:

• Apple Silicon https://desktop-stage.docker.com/mac/main/arm64/195474/Docker.dmg
• Intel https://desktop-stage.docker.com/mac/main/amd64/195474/Docker.dmg

Let me know what happens if you get a chance to try it!

[cristianrgreco]

Thanks @djs55. Can confirm the Apple Silicon build fixes the issue for me. Is there any ETA on an official release update?

[jbxonline]

Thanks for the quick work @djs55
Can confirm it is working for me on Apple Silicon.

[devantler]

Works for me as well (Apple Silicon) ❤️

• Fixes [bug]: Docker host ports not working all of a sudden. devantler-tech/ksail#1163

[uliilu]

The test build also works for me on a 2019 Intel Mac.