Issue mounting NFS share with Ubuntu 22.04

I have a QNAP NAS with NFS shares on my LAN and am trying to mount them on my mostly vanilla Ubuntu 22.04 install.

Running showmount on the client shows the NFS shares:

~$ showmount -e nas.localdomain
Export list for nas.localdomain:
/Videos *
/Public *
/Games *
/Download *

The mount command completes successfully...

~$ sudo mount -t nfs nas.localdomain:/ /mnt/nas

... however trying to do anything in the mounted directory hangs (e.g. ls). Nautilus shows the top-level shared directories, but also hangs on trying to access them.

Oddly enough I have 2 other laptops, one running Ubuntu 21.04 and another one running Manjaro, and they both can mount the NAS shares with the exact same command without any problem, so the issue is most likely not with the NFS server but rather the client.

Any idea on how to solve this?

1 Answer

Realized there are already a couple similar questions like unable to mount nfs on Ubuntu 22.04. The answers there weren't actually working for me (I was getting mount.nfs4: requested NFS version or transport protocol is not supported trying to use -o vers=3 or mountvers=4.0) but after some tinkering the following command worked:

~$ sudo mount -t nfs -o vers=4.0 nas.localdomain:/ /mnt/nas

Still unclear what changed in the recent version of Ubuntu though... Reading it seems like there is some compatibility issue with NFS 4.2.