[WSL 2.9.3] Docker fails to bind ports with "address already in use" when networkingMode=mirrored is enabled

[gsdukbh]

Windows Version

Microsoft Windows [version 10.0.26200.8246]

WSL Version

2.9.3.0

Are you using WSL 1 or WSL 2?

• WSL 2
• WSL 1

Kernel Version

Linux version 6.18.35.2-microsoft-standard-WSL2

Distro Version

Ubuntu 22.04

Other Software

• Docker Desktop or Docker Engine running inside WSL
• Docker Compose

Repro Steps

1. Upgrade WSL to version 2.9.3 (pre-release).
2. Enable mirrored networking by adding the following to %USERPROFILE%\.wslconfig:

   [wsl2]
   networkingMode=mirrored

1 .Restart WSL completely (wsl --shutdown).
2. Attempt to start a Docker container that exposes a port to the host (e.g., 0.0.0.0:8003:8003). I was trying to run Immich via docker-compose up -d.


### Expected Behavior

The Docker container should start successfully, bind to the port, and the service should be accessible via both localhost:8003 and the Windows host's LAN IP address (e.g., http://192.168.1.39:8003/


### Actual Behavior

Docker fails to start the container and throws the following endpoint connectivity error:
> Error response from daemon: failed to set up container networking: driver failed programming external connectivity on endpoint immich_server (...): failed to bind host port 0.0.0.0:8003/tcp: address already in use

Troubleshooting Performed (To rule out user errors)
I have thoroughly checked both the Windows host and the WSL environment to ensure the port is truly available. The issue persists despite confirming the following:

1. No WinNAT Port Reservation: Checked netsh interface ipv4 show excludedportrange protocol=tcp in Windows. Port 8003 is NOT in the excluded range. Restarting WinNAT (net stop winnat / net start winnat) did not help.
2. No Windows Processes Using the Port: Ran netstat -ano | findstr :8003 on Windows. No output.
3. No WSL/Docker Zombie Processes: Ran docker ps -a and sudo ss -tulpn | grep 8003 inside WSL. No leftover containers or docker-proxy processes are holding the port.
4. No PortProxy Conflicts: Verified that there are no conflicting netsh interface portproxy rules active.
5. Successful Downgrade: After safely downgrading WSL from 2.9.3 back to 2.7.10 (and reverting to NAT mode), the network behavior returned to normal, confirming this is a regression or bug specific to the newer pre-release and the mirrored networking mode.


### Diagnostic Logs

_No response_

[github-actions]

Logs are required for review from WSL team

If this a feature request, please reply with '/feature'. If this is a question, reply with '/question'.
Otherwise, please attach logs by following the instructions below, your issue will not be reviewed unless they are added. These logs will help us understand what is going on in your machine.

How to collect WSL logs

Download and execute collect-wsl-logs.ps1 in an administrative powershell prompt:

Invoke-WebRequest -UseBasicParsing "https://raw.githubusercontent.com/microsoft/WSL/master/diagnostics/collect-wsl-logs.ps1" -OutFile collect-wsl-logs.ps1
Set-ExecutionPolicy Bypass -Scope Process -Force
.\collect-wsl-logs.ps1

The script will output the path of the log file once done.

If this is a networking issue, please use .\collect-wsl-logs.ps1 -LogProfile networking instead, following the instructions in Collect WSL logs for networking issues

Once completed please upload the output files to this GitHub issue.

See Collect WSL logs (recommended method).

If you choose to email these logs instead of attaching them to the bug, please send them to wsl-gh-logs@microsoft.com with the GitHub issue number in the subject, and include a link to your GitHub issue comment in the message body, and reply with '/emailed-logs'.

[gsdukbh]

Logs are required for review from WSL team

If this a feature request, please reply with '/feature'. If this is a question, reply with '/question'. Otherwise, please attach logs by following the instructions below, your issue will not be reviewed unless they are added. These logs will help us understand what is going on in your machine.

How to collect WSL logs

/question

[github-actions]

Diagnostic information

Found '/question', adding tag 'question'

[OneBlue]

/logs

[gsdukbh]

WslLogs-2026-07-03_08-40-21.tar.gz

[github-actions]

Diagnostic information

.wslconfig found
Detected appx version: 2.7.10.0

[gsdukbh]

Diagnostic information

.wslconfig found
Detected appx version: 2.7.10.0

After upgrading to 2.9.3 and encountering issues, I downgraded to 2.7.10.0. However, the problem persists