WSL2 Networking issue when accessing nat/bridged localhost

[mxschmitt]

Description

When using WSL2 on GitHub Actions in the Windows image its not possible to access the hosts's localhost network.

According to the documentation it should be possible. On my personal notebook / Windows DevBox this works as well. This makes it hard for us (Playwright) to test a feature which relies on WSL under the hood.

Platforms affected

• Azure DevOps
• GitHub Actions - Standard Runners
• GitHub Actions - Larger Runners

Runner images affected

• Ubuntu 22.04
• Ubuntu 24.04
• macOS 13
• macOS 13 Arm64
• macOS 14
• macOS 14 Arm64
• macOS 15
• macOS 15 Arm64
• Windows Server 2019
• Windows Server 2022
• Windows Server 2025

Image version and build link

Image: windows-2025
Version: 20250617.1.0
Included Software: https://github.com/actions/runner-images/blob/win25/20250617.1/images/windows/Windows2025-Readme.md
Image Release: https://github.com/actions/runner-images/releases/tag/win25%2F20250617.1

Is it regression?

No

Expected behavior

It works.

Actual behavior

Timeout / WSL2 is not able to access the Windows host's networking.

Repro steps

Repro: https://github.com/mxschmitt/github-actions-windows-wsl-networking-localhost

[vidyasagarnimmagaddi]

Hi @mxschmitt ,Thank you for bringing this issue to our attention. We will look into this issue and will update you after investigating.

[mxschmitt]

Investigation: Looks like something related to the Firewall - when adding a rule with a custom allow rule it seems to work: mxschmitt/github-actions-windows-wsl-networking-localhost#1

This seems to be very hard to use tho - I think it would be great if we could make that work out of the box!

Its also a bit of unfortunate since the wsl --install needs to run before. Probably before the network interface is not there.

[hemanthmanga]

Hi @mxschmitt, Thanks for sharing your findings,

Looks like something related to the Firewall

Yes, Windows Firewall blocks WSL2 from connecting to the Windows host, I reviewed your workflow file, adding a custom allow rule fix the issue. However, as you mentioned, it's difficult to automate, especially in CI environments, because the WSL network interface appears only after running wsl --install.

At the moment, we can't make this work smoothly on GitHub-hosted runners due to architectural constraints in WSL2 and Windows networking. We are keeping an eye on updates from Microsoft that might make this easier in the future.
For now, if you need custom networking or firewall configurations, we recommend using self-hosted runners.

Kindly review these known issues for additional information: microsoft/WSL#4619, microsoft/WSL#4139, Closing this issue.