WSL2: Jumbo frames are not forwarded to mirrored interface on Linux

[mgkbeer]

Windows Version

Windows version: 10.0.22621.3007

WSL Version

WSL version: 2.1.0.0

Are you using WSL 1 or WSL 2?

• WSL 2
• WSL 1

Kernel Version

Ubuntu-22.04

Distro Version

Ubuntu-22.04

Other Software

No response

Repro Steps

[wsl2]
networkingMode = mirrored
firewall=true

localhostforwarding = true

Sending Ethernet packets of size 5000 bytes. I see those on Windows but do not see those on Ubuntu's mirrored interface. I do see packets less than 1500 bytes

Expected Behavior

Expected behavior is that I do see all the packets on mirrored interface

Actual Behavior

No packets bigger the 1500 bytes are seen

Diagnostic Logs

No response

[github-actions]

Hi I'm an AI powered bot that finds similar issues based off the issue title.

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. Thank you!

Open similar issues:

• Networking mirrored can't work on WSL2 (#10632), similarity score: 0.73

Note: You can give me feedback by thumbs upping or thumbs downing this comment.

[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

[Ricardo-Evans]

I also meet the same problem, is there any specific reason why WSL cannot support jumbo frames?

[arobicha]

Here's an example that captures the issue in logs.

Context is that I have AlmaLinux-9 running in WSL2 on a Windows 11 machine. Client application (192.168.42.2) is expecting 19164 jumbo packets of length 6466 or 6498 from a device on our local network (192.168.42.1). pktmon.etl captures those packets, but tcpdump does not.

WslNetworkingLogs-2025-02-04_14-52-07.zip