WSL 2 mirrored networking breaks NFS mounts (“Connection timed out”)

[wpwoodjr]

Windows Version

Microsoft Windows [Version 10.0.26100.2894]

WSL Version

WSL version: 2.3.26.0 Kernel version: 5.15.167.4-1 WSLg version: 1.0.65 MSRDC version: 1.2.5620 Direct3D version: 1.611.1-81528511 DXCore version: 10.0.26100.1-240331-1435.ge-release Windows version: 10.0.26100.2894

Are you using WSL 1 or WSL 2?

• WSL 2
• WSL 1

Kernel Version

5.15.167.4-microsoft-standard-WSL2

Distro Version

Ubuntu 22.04.5 LTS

Other Software

When using WSL 2 mirrored networking mode, any attempt to mount an NFS share from within WSL 2 fails with errors:

$ sudo mount -v -t nfs ub-nuc:/home/wpwoodjr /home/wpwoodjr/ub-nuc
mount.nfs: timeout set for Mon Jan 27 13:45:44 2025
mount.nfs: trying text-based options 'vers=4.2,addr=192.168.86.200,clientaddr=192.168.86.41'
mount.nfs: mount(2): Invalid argument
mount.nfs: trying text-based options 'vers=4,minorversion=1,addr=192.168.86.200,clientaddr=192.168.86.41'
mount.nfs: mount(2): Connection timed out
mount.nfs: Connection timed out

Key Observations

• Mount works from other Linux clients on the same network (e.g., a Raspberry Pi).
• Mount works if I revert WSL 2 to the legacy NAT networking mode.
• Turning off Windows Firewall does not help.
• Pinging or otherwise accessing the NFS server (e.g. rpcinfo -p serverIP) still works, but mount -t nfs … fails.

Request

• Fix or provide guidance on how to use mirrored networking with protocols like NFS that may rely on particular port/protocol interactions.
• Alternatively, document known limitations of mirrored networking mode for advanced protocols.

Thank you for looking into this issue!

Repro Steps

Enable mirrored networking (set networkingMode=mirrored in .wslconfig).
Install NFS client tools in WSL:

sudo apt-get update
sudo apt-get install nfs-common

Attempt to mount an exported NFS share:

sudo mount -v -t nfs serverIP:/path /mnt/test

The command eventually returns an error:

mount.nfs: mount: Connection timed out

Expected Behavior

The NFS share should mount successfully inside WSL 2, just like it does from a Raspberry Pi or other standard Linux environment on the same LAN.

Actual Behavior

The mount attempt times out.
No traffic is visibly blocked by the Windows Firewall (which I turned off for testing).
Reverting to non-mirrored networking mode in .wslconfig and restarting WSL immediately fixes the issue.
So it appears mirrored networking specifically interferes with NFS.

Diagnostic Logs

From wsl client with mirrored networking:

$ rpcinfo -p
   program vers proto   port  service
    100000    4   tcp    111  portmapper
    100000    3   tcp    111  portmapper
    100000    2   tcp    111  portmapper
    100000    4   udp    111  portmapper
    100000    3   udp    111  portmapper
    100000    2   udp    111  portmapper

$ showmount -e ub-nuc
Export list for ub-nuc:
/home/wpwoodjr 192.168.86.0/24

$ nc -vz ub-nuc 2049
Connection to ub-nuc (192.168.86.200) 2049 port [tcp/nfs] succeeded!

$ sudo mount -v -t nfs ub-nuc:/home/wpwoodjr /home/wpwoodjr/ub-nuc
mount.nfs: timeout set for Mon Jan 27 13:45:44 2025
mount.nfs: trying text-based options 'vers=4.2,addr=192.168.86.200,clientaddr=192.168.86.41'
mount.nfs: mount(2): Invalid argument
mount.nfs: trying text-based options 'vers=4,minorversion=1,addr=192.168.86.200,clientaddr=192.168.86.41'
mount.nfs: mount(2): Connection timed out
mount.nfs: Connection timed out

After disabling mirrored networking:

$ sudo mount -v -t nfs ub-nuc:/home/wpwoodjr /home/wpwoodjr/ub-nuc
mount.nfs: timeout set for Mon Jan 27 14:44:39 2025
mount.nfs: trying text-based options 'vers=4.2,addr=192.168.86.200,clientaddr=172.24.87.14'
mount.nfs: mount(2): Invalid argument
mount.nfs: trying text-based options 'vers=4,minorversion=1,addr=192.168.86.200,clientaddr=172.24.87.14'

$ ls ub-nuc
Desktop    Downloads   Music     Public     Videos      linux-dev    snap             win10.log
Documents  ...

[github-actions]

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Invoke-WebRequest -UseBasicParsing "https://raw.githubusercontent.com/microsoft/WSL/master/diagnostics/collect-wsl-logs.ps1" -OutFile collect-wsl-logs.ps1
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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:

• With WSL2's Mirror Network Mode, Services on the Windows Host are Inaccessible, but the Reverse is Possible (#12399), similarity score: 0.74

Closed similar issues:

• Can't mount NFS from within WSL2 Ubuntu 22.04 (#9790), similarity score: 0.75
• NFS cannot be used in WSL (#10331), similarity score: 0.72
• WSL 2 can't mount NFS share (#8640), similarity score: 0.72
• Networking mirrored can't work on WSL2 (#10632), similarity score: 0.72

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

[wpwoodjr]

Logs attached

WslLogs-2025-01-27_15-28-25.zip

[github-actions]

Diagnostic information

.wslconfig found
Detected appx version: 2.3.26.0

[dezerving]

Just want to confirm that I am seeing the same thing after upgrading wsl with bridged mode being deprecated.

NFS is completely broken in wsl2 with mirrored networking, works fine on my other Linux boxes.

Info:

WSL version: 2.3.26.0
Kernel version: 5.15.167.4-1
WSLg version: 1.0.65
MSRDC version: 1.2.5620
Direct3D version: 1.611.1-81528511
DXCore version: 10.0.26100.1-240331-1435.ge-release
Windows version: 10.0.26100.2894

Logs: WslLogs-2025-01-31_18-26-08.zip

Networking Logs: WslNetworkingLogs-2025-01-31_18-28-01.zip

[ljcbaby]

same issue