WSL seems to limit TCP sockets

[ephemeris-lappis]

Windows Version

Microsoft Windows [version 10.0.22631.4460]

WSL Version

2.3.26.0

Are you using WSL 1 or WSL 2?

• WSL 2
• WSL 1

Kernel Version

Debian 5.15.167.4-microsoft-standard-WSL2 + Ubuntu 5.15.167.4-microsoft-standard-WSL2

Distro Version

Debian 10 + Ubuntu 22.04

Other Software

No response

Repro Steps

I'm working with to Linux distributions in WSL 2.
Kubernetes tools (kubectl, kubtctx, kubens) are installed on both : this allows connecting to distinct clusters.
I usually use port forwarding to allow accesses to different services on different pods of different namespaces.
This generally works.
When using Apache JMeter (for example) to execute load tests, many sockets my be opened.
It seems that when the opened sockets reach about 1000 (1024 ?) new connections fail.
After looking for Kubernetes or Windows limitations, I can confirm that connecting to any host from Windows or Linux is still possible while new sockets across WSL fail.
When this limit seems to be reached, whatever Linux is used, the only way to recover a normal behavior is after executing "wsl --shutdown".

Expected Behavior

No limit on TCP sockets.

Actual Behavior

Diagnostic Logs

No response

[github-actions]

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.\collect-wsl-logs.ps1

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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:

• WSL network crashes after 100 ssh connections (#11759), similarity score: 0.71

Closed similar issues:

• WSL steals UDP Ports from Windows (#12228), similarity score: 0.76
• Unable to connect to existing WSL instance because socket already exists in /run/WSL (#7252), similarity score: 0.71
• TCP ephemeral ports exhausted and network broken after lots of early-closed non-blocking connections (#2913), similarity score: 0.71
• WSL2 and Windows can bind listening TCP socket on 127.0.0.1 using same port without setting SO_REUSEADDR (#7150), similarity score: 0.71

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[ephemeris-lappis]

Logs !
WslLogs-2024-12-16_09-01-22.zip

[github-actions]

Diagnostic information

Detected appx version: 2.3.26.0

[OneBlue]

Thank you for reporting this @ephemeris-lappis. Can you share an strace of the process that's failing to create sockets ? I'm curious to see what the socket() error code is

[ephemeris-lappis]

Here are two trace files, one from process monitor tracking a JConsole trying to connect to a distant JVM, and the corresponding WireShark's TCP exchanges.

The TCP flow seems to end prematurally with an inexpected RST.

The test is done after a JMeter executions that creates more than 1000 ActiveMQ connections, almost all failing. Even when the tests ended, no more connection can be succesfully established on any WSL instance (I have two Linux).

Note that any network activity from Windows is still working (LAN, Internet, etc.), except when the target is across WSL. And, as I said before, shutting down WSL is the only way to recover a normal connectivity.

I hope this can help you. Be free to ask for more details if needed.

traces.zip

[github-actions]

Failed to parse logs. Unexpected file: jconsole.pcap
The log file doesn't contain any WSL traces. Please make sure that you reproduced the issue while the log collection was running.

Diagnostic information

Found no WSL traces in the logs

[ephemeris-lappis]

Thank you for reporting this @ephemeris-lappis. Can you share an strace of the process that's failing to create sockets ? I'm curious to see what the socket() error code is

Hello !
I've uploaded a zip with two files, but the robot seems to ask me for more logs...
Is it actually necessary ?