Ventura as NFS Server: Client reports Protocol not supported

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Level 1

13 points

Ventura as NFS Server: Client reports Protocol not supported

I'm trying to mount a volume on an external hard disk connected to my MacBook Pro (16", 2021) on a Linux box running an offshoot of RedHat Enterprise Linux. Here is my /etc/exports file on the Mac:

/Volumes/Passport -mapall=501 -network 192.168.0.0 -mask 255.255.255.0

where 501 is the UID of the local user who has full permission to write to the directory on the volume that I wish to mount. The purpose is to do a backup of certain directories on the Linux box.

showmount -e verifies that nfsd is enabled and running.

Here is the command given on the Linux box and the output (in full, in case it is helpful):

% sudo mount -v -t nfs macbookpro:/Volumes/Passport /mac/backup

[sudo] password for <user>:

mount.nfs: timeout set for Thu Dec 22 09:22:40 2022

mount.nfs: trying text-based options 'vers=4.1,addr=192.168.0.3,clientaddr=192.168.0.2'

mount.nfs: mount(2): Protocol not supported

mount.nfs: trying text-based options 'vers=4.0,addr=192.168.0.3,clientaddr=192.168.0.2'

mount.nfs: mount(2): Protocol not supported

mount.nfs: trying text-based options 'addr=192.168.0.3'

mount.nfs: prog 100003, trying vers=3, prot=6

mount.nfs: trying 192.168.0.3 prog 100003 vers 3 prot TCP port 2049

mount.nfs: prog 100005, trying vers=3, prot=17

mount.nfs: trying 192.168.0.3 prog 100005 vers 3 prot UDP port 748

mount.nfs: mount(2): Device or resource busy

mount.nfs: Protocol not supported

Can anyone tell me why this doesn't work and/or how to fix it?

MacBook Pro Apple Silicon

Posted on Dec 22, 2022 6:24 AM

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Answer 1

etresoft

Level 8

46,458 points

Dec 22, 2022 7:35 AM in response to elisatems

What version of macOS are you using? I was able to do this easily enough with Monterey. The only tricky part was that I had to give nfsd Full Disk Access in System Preferences > Security & Privacy. Apple already includes smbd in that list, so it makes sense.

External volumes are "protected" areas like Desktop, Documents, and Downloads. However, there is no associated UI to prompt you to allow access in nfsd. The only way to accomplish this is to short-circuit the process with Full Disk Access.

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Answer 2

elisatems Author

Level 1

13 points

Dec 22, 2022 8:31 AM in response to etresoft

Update: found the answer, with the help of some notes from the author of the NFS Manager tool (which I've tried, and which was helpful in setting server-side permissions)... the critical missing option was "-o rsize=65536". Apparently a buffer size mismatch, easily fixed. So, problem solved!

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Answer 3

elisatems Author

Level 1

13 points

Dec 22, 2022 8:16 AM in response to etresoft

Well, as the subject says, I'm running Ventura (13.1). Full Disk Access is enabled for nfsd, so that isn't the issue. Does it need to be enabled for any other processes? What version of the nfs protocol does nfsd use on MacOS?

I should say that I was able to do this for many years without issue under Mojave. Then I tried this after upgrading to Big Sur a year ago or so, and encountered the same problem as I'm reporting now. Was hoping that it was a glitch that wouldn't be present under Ventura, but apparently it is a protocol incompatibility of some sort between post-Mojave or post-Catalina versions of nfsd under MacOS and what the Linux mount command knows how to try. If I knew the exact version and protocol numbers, I could pass them in the mount command, but this info doesn't seem to be documented anywhere.

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