mDNS does not work with mirrored network mode

[lprobsth]

Windows Version

Microsoft Windows [Version 10.0.22631.3880]

WSL Version

2.2.4.0

Are you using WSL 1 or WSL 2?

• WSL 2
• WSL 1

Kernel Version

5.15.153.1-2

Distro Version

Ubuntu 22.04

Other Software

No response

Repro Steps

• Install WSL2 with Ubuntu
• Enable mirrored network mode:

# Settings apply across all Linux distros running on WSL 2
[wsl2]

networkingMode=mirrored

• Ping a device in the same network as the computer with its local hostname:

ping server.local

Expected Behavior

WSL2 should correctly resolve the local / mDNS hostname to the correct IP address:

$ ping server.local
PING 192.168.178.53 (192.168.178.53) 56(84) bytes of data.
64 bytes from 192.168.178.53: icmp_seq=1 ttl=64 time=3.98 ms
64 bytes from 192.168.178.53: icmp_seq=2 ttl=64 time=2.20 ms
64 bytes from 192.168.178.53: icmp_seq=3 ttl=64 time=2.81 ms

Actual Behavior

The mDNS hostname is not resolved:

ping: server.local: Name or service not known

Diagnostic Logs

WslLogs-2024-07-29_18-57-01.zip

[github-actions]

View similar issues

Please view the issues below to see if they solve your problem, and if the issue describes your problem please consider closing this one and thumbs upping the other issue to help us prioritize it!

Open similar issues:

• Mirrored Network: Local DNS resolution does not work (#11199), similarity score: 0.83
• No network access with networkingMode=mirrored (#10791), similarity score: 0.79

Closed similar issues:

• Networking mode does not work in mirrored mode (#11540), similarity score: 0.78
• Networking mirrored (#10652), similarity score: 0.77
• Networking mirrored can't work on WSL2 (#10632), similarity score: 0.77

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Diagnostic information

.wslconfig found
Detected appx version: 2.2.4.0

[Revono]

Same issue here WSL2 Ubuntu

[Emaro]

I have the same issue. A fix would be appreciated.

[CatalinFetoiu]

thanks for reporting the issue

we have updated the docs to include details about how to resolve .local names in WSL. Please refer to https://learn.microsoft.com/en-us/windows/wsl/troubleshooting#resolve-local-names-in-wsl

let us know if you have any questions

[lprobsth]

I tried the configuration with libnss-mdns and nsswitch.conf from the docs but it does not work. Is there something else I can provide?

[CatalinFetoiu]

@lprobsth thanks for following up
please make sure you are using latest WSL build (2.3.17)
I recommend also confirming that mirrored mode was successfully enabled - you can do this by running "wslinfo --networking-mode" in your distro

if you still encounter issues after confirming the above, please collect networking logs using instructions at https://github.com/microsoft/WSL/blob/master/CONTRIBUTING.md#collect-wsl-logs-for-networking-issues

[lprobsth]

I have installed WSL build 2.3.17. The problem seems to persist.

Here is the log file. The networking log script did not create an archive - so I zipped the output from the log directory. I hope this is correct.

WslNetworkingLogs-2024-08-22_16-09-18.zip

[github-actions]

Diagnostic information

.wslconfig found
Detected appx version: 2.3.17.0
optional-components.txt not found

[CatalinFetoiu]

@lprobsth thanks

the logs don't show mdns traffic being sent by Linux

could you please collect and share the output of "sudo strace ping server.local" ? that might give us a hint on why no mdns requests are sent