I have a proprietary NAS server than provides SMB services to access its content. The SMB protocol is stick to the V1.0 (can't changed that).

I also have a ubuntu 20.04 server than should access to this NAS. Specifically, I use the NAS to store copy of data, writen by a Synthing service. The same NAS is also accessed from windows computers.

Here's my fstab entry :

//mynashost/SomeShare /mnt/SomeShare cifs    vers=1.0,guest,uid=1000,gid=1000,comment=cloudconfig,iocharset=utf8     0       0

This works well for my main user (which is uid 1000 and gid 1000), but not for other users. Specifically, my syncthing service is running using a dedicated user account.

This other user is able to read the content, but not able to write (permission denied).

Trying to chown the folders within the share doesn't work (permission denied) even using sudo.

I'm very confused regarding the fstab options related to security. How to fix my option to let any user of my server read and write data ?

Since it's a home server, I have no requirement to isolate each user, mounting the NAS anonymously is an option if it helps.

  • I have an rw statement before uuid=1000,gid=500 for cifs access to my Synology NAS which works perfectly between different PCs on the local network.
    – 24601
    May 5, 2021 at 7:19
  • Have you tried changing the permissions of the /mnt/SomeShare folder to make it writable for all users?
    – Stormlord
    May 5, 2021 at 13:18

1 Answer 1


I finally found the correct combination. Here's my updated fstab:

//mynashost/SomeShare /mnt/SomeShare cifs    vers=1.0,guest,uid=1000,gid=1000,comment=cloudconfig,iocharset=utf8,noperm      0       0

The point is the addition of noperm option.

Here's the mount.cifs manpage related excerpt:

noperm Client does not do permission checks. This can expose files on this mount to access by other users on the local client system. It is typically only needed when the server supports the CIFS Unix Extensions but the UIDs/GIDs on the client and server system do not match closely enough to allow access by the user doing the mount. Note that this does not affect the normal ACL check on the target machine done by the server software (of the server ACL against the user name provided at mount time).

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