Windows programs unable to communicate on localhost, maybe due to mirrored mode wsl bug.

[peigongdsd]

Windows Version

Microsoft Windows [Version 10.0.26090.112]

WSL Version

WSL version: 2.2.1.0 Kernel version: 5.15.150.1-2 WSLg version: 1.0.60 MSRDC version: 1.2.5105 Direct3D version: 1.611.1-81528511 DXCore version: 10.0.25131.1002-220531-1700.rs-onecore-base2-hyp Windows version: 10.0.26090.112

Are you using WSL 1 or WSL 2?

• WSL 2
• WSL 1

Kernel Version

5.15.150.1-microsoft-standard-WSL2

Distro Version

PRETTY_NAME="Ubuntu 22.04.3 LTS" NAME="Ubuntu" VERSION_ID="22.04" VERSION="22.04.3 LTS (Jammy Jellyfish)" VERSION_CODENAME=jammy ID=ubuntu ID_LIKE=debian HOME_URL="https://www.ubuntu.com/" SUPPORT_URL="https://help.ubuntu.com/" BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/" PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy" UBUNTU_CODENAME=jammy

Other Software

No response

Repro Steps

• Reboot the machine.
• After boot, try to connect to TCP services on localhost, from windows to windows. For example, an http server listening on localhost.
• All the requests fail. The http page fails to load. Use wireshark to inspect the packages, and it seems that only part of the TCP stream is transmitted. This can also be seen by using curl or browser developer tools.
• Start wsl, in network=NAT mode. Then request again.
• Nothing changes.
• Restart wsl in network=mirrored mode. Request.
• Now everything suddenly works fluently. Http request from windows to windows work. Very wired.
• Stop wsl, and things still work.

Expected Behavior

As above.

Actual Behavior

As above.

Diagnostic Logs

No response

[github-actions]

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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:

• Localhost is not accessible from windows in mirrored mode (#11172), similarity score: 0.79
• High network connection delay when using mirrored networking using "localhost" (#11186), similarity score: 0.79

Closed similar issues:

• Networking mirrored can't work on WSL2 (#10632), similarity score: 0.80
• WSL 2.0.6 mirrored network - can not connect to Docker container ports from Windows host (#10683), similarity score: 0.79
• In Mirrored mode incoming packets from remote device on LAN are not received in WSL2 (#10535), similarity score: 0.79

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[peigongdsd]

Well, just rebooting my machine to capture the bug.
This is the screenshot when I was trying to connect to sing-box dashboard on 127.0.0.1:9090/ui.

Seems the response TCP package is truncated. Here is another experiment. Use miniserve to serve a folder on port 3015, localhost, and try to connect. At first the connection just die, but when wsl is started, the connection suddenly works.

output.mp4

[peigongdsd]

This is very annoying since it has happened for quite a while, and I need to start wsl every time on windows boot. I tried to debug this but due to lack of knowledge of the internal mechanism of mirrored mode network of wsl and windows network stack, little could be done.

[chanpreetdhanjal]

Hi. Can you please collect networking logs by following the instructions below?
https://github.com/microsoft/WSL/blob/master/CONTRIBUTING.md#collect-wsl-logs-for-networking-issues