NFS client “Permission Denied” on Debian unstable

While I was trying to access to a master NFS server in lenny from a squeeze client, I was having “Permission denied” when I tried to write any file; as there are other NFS clients with the same configuration this didn’t seem to be a problem of NFS configuration but rather from new client version.

After some googling time, I found this bug:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=492970

If you want to know if your version is having this problem, you can check doing a “cat /proc/mounts” and should see the NFS mount with a “sec=null” and that is giving you the problem.

A suggestion from bug report is to downgrade, but that could not be an option in a fresh installed squeeze so the other workaround is easy:

  1. Unmount all nfs (important as I only unmount a exported filesystem from a server and won’t work until you unmount all)
  2. On /etc/fstab (or when mounting if you are doing manual) add the option sec=sys to all the mounts for that server; for example in fstab:
    example.com:/shared /tmp/shared nfs rw,sec=sys 0 0

    or mounting:

    mount -t nfs  -o "rw,sec=sys" example.com:/shared /tmp/shared

  3. Mount all nfs from that server

If you check the /proc/mounts you should see the sec=sys instead null and be able to write to remote server

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  • Maiko

    Hi, I’ve tried it without luck. Searching a little more I discover that the permissions of the exported NFS directory (on the server) needs to have the same file permissions that the user which are mounting it.

    so for example, executing the line bellow on the NFS server can solve the problem if you are mounting as root in the client.

    chown -R root:root /srv/

    bye.