UDP source ports can't be reused after 120s

[jamilbk]

Description

Hello, we've hit a strange issue where Docker Desktop for Mac drops UDP packets if they reuse a source port after 120s (the macOS kernel NAT binding session duration). When this occurs, tcpdump reveals that no packets are seen reaching the host's network interface, so the source of the issue is unlikely to be macOS.

The issue does not occur if the UDP traffic is sent every 120s or below, or a different source port is used.

The issue occurs using a fresh install of Docker Desktop v4.37.2 on macOS 15.2 on an M1 chip.

Reproduce

Here is a minimal docker-compose.yml that highlights the issue using DNS:

services:
  dig:
    image: alpine
    command:
      - /bin/sh
      - -c
      - |
        apk add -u cmd:dig

        # Pick a random source port
        source_port=$(shuf -i 60000-61000 -n 1)
        echo
        echo "Source port: $$source_port"
        echo

        # Perform query, creating NAT binding
        dig -b 0.0.0.0#$$source_port @1.1.1.1 google.com

        # Wait for 121s
        echo
        echo "Sleeping for 121 seconds..."
        sleep 121

        # Query again, fails
        echo
        dig @1.1.1.1 -b 0.0.0.0#$$source_port google.com

Expected behavior

UDP traffic should correctly be routed out of the host interface and responses routed back to the container making the requests.

docker version

Client:
 Version:           27.4.0
 API version:       1.47
 Go version:        go1.22.10
 Git commit:        bde2b89
 Built:             Sat Dec  7 10:35:43 2024
 OS/Arch:           darwin/arm64
 Context:           desktop-linux

Server: Docker Desktop 4.37.2 (179585)
 Engine:
  Version:          27.4.0
  API version:      1.47 (minimum version 1.24)
  Go version:       go1.22.10
  Git commit:       92a8393
  Built:            Sat Dec  7 10:38:33 2024
  OS/Arch:          linux/arm64
  Experimental:     false
 containerd:
  Version:          1.7.21
  GitCommit:        472731909fa34bd7bc9c087e4c27943f9835f111
 runc:
  Version:          1.1.13
  GitCommit:        v1.1.13-0-g58aa920
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

docker info

Client:
 Version:    27.4.0
 Context:    desktop-linux
 Debug Mode: false
 Plugins:
  ai: Ask Gordon - Docker Agent (Docker Inc.)
    Version:  v0.5.1
    Path:     /Users/jamil/.docker/cli-plugins/docker-ai
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.19.2-desktop.1
    Path:     /Users/jamil/.docker/cli-plugins/docker-buildx
  compose: Docker Compose (Docker Inc.)
    Version:  v2.31.0-desktop.2
    Path:     /Users/jamil/.docker/cli-plugins/docker-compose
  debug: Get a shell into any image or container (Docker Inc.)
    Version:  0.0.37
    Path:     /Users/jamil/.docker/cli-plugins/docker-debug
  desktop: Docker Desktop commands (Beta) (Docker Inc.)
    Version:  v0.1.0
    Path:     /Users/jamil/.docker/cli-plugins/docker-desktop
  dev: Docker Dev Environments (Docker Inc.)
    Version:  v0.1.2
    Path:     /Users/jamil/.docker/cli-plugins/docker-dev
  extension: Manages Docker extensions (Docker Inc.)
    Version:  v0.2.27
    Path:     /Users/jamil/.docker/cli-plugins/docker-extension
  feedback: Provide feedback, right in your terminal! (Docker Inc.)
    Version:  v1.0.5
    Path:     /Users/jamil/.docker/cli-plugins/docker-feedback
  init: Creates Docker-related starter files for your project (Docker Inc.)
    Version:  v1.4.0
    Path:     /Users/jamil/.docker/cli-plugins/docker-init
  sbom: View the packaged-based Software Bill Of Materials (SBOM) for an image (Anchore Inc.)
    Version:  0.6.0
    Path:     /Users/jamil/.docker/cli-plugins/docker-sbom
  scout: Docker Scout (Docker Inc.)
    Version:  v1.15.1
    Path:     /Users/jamil/.docker/cli-plugins/docker-scout

Server:
 Containers: 10
  Running: 8
  Paused: 0
  Stopped: 2
 Images: 30
 Server Version: 27.4.0
 Storage Driver: overlayfs
  driver-type: io.containerd.snapshotter.v1
 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
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 472731909fa34bd7bc9c087e4c27943f9835f111
 runc version: v1.1.13-0-g58aa920
 init version: de40ad0
 Security Options:
  seccomp
   Profile: unconfined
  cgroupns
 Kernel Version: 6.10.14-linuxkit
 Operating System: Docker Desktop
 OSType: linux
 Architecture: aarch64
 CPUs: 8
 Total Memory: 7.654GiB
 Name: docker-desktop
 ID: 8c2fb06c-d85c-49c4-b306-f9cb306d9483
 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/jamil/Library/Containers/com.docker.docker/Data/docker-cli.sock
 Experimental: false
 Insecure Registries:
  hubproxy.docker.internal:5555
  127.0.0.0/8
 Live Restore Enabled: false

Diagnostics ID

7278E4AE-74CD-4E52-BADE-921484E4E12C/20250121193609

Additional Info

No response

[jamilbk]

One more piece of info: only restarting the Docker daemon (Docker for Mac) resets the issue. Tearing down the container and associated resources doesn't seem to make a difference.

[gonzaloalvarez4]

I've faced the same issue with Docker Desktop for Windows.
Only reverting to Docker Desktop 4.5.1 version solved the issue for me. Is a really old version but the newest working without the issue...