Linux autofs CIFS mount of FRITZ!Box NAS

2020-10-26 : Accessing a cifs mount with autofs.

Accessing a NAS from your Linux laptop should be done with autofs rather than fstab, because the automounter will reestablish the remote filesystem access automatically should you loose your wifi connection now and then.

In my home setup i have a FRITZ!Box 7490 serving an USB 3.0 SSD as my local NAS to be accessed by multiple different devices. Some of these are Linux laptops running an openSUSE 15.2 distribution. The NAS itself supported the SMB 1 protocol only in the past, but after upgrading to a newer FRITZ!OS i can use SMB 3 now.

To get the automounter service running, i had to install it first because it wasn't part of a default installation:

$> zypper in autofs

I want to access the NAS with the mount point /fritz.box, therefore i created that directory first with mkdir /fritz.box. After that i edited the file /etc/auto.master, the main configuration file of the automounter, by adding the line:

/-    /etc/auto.direct

After the above mentioned file /etc/auto.direct was created by myself i wrote the following line into it to access my NAS dynamically with the automounter:

/fritz.box   -fstype=cifs,rw,uid=${UID},gid=users,noserverino,cache=none,file_mode=0664,dir_mode=0775,username=cifsuser,password=XXXXX   ://fritz.box/fritz.nas

Most of the parameters should be self-explanatory (for cache=none see my other article). I created an explicit cifsuser account on the FRITZ!Box NAS server first before using it here for the connection authorization. If you need to, you could include these authorization credentials from an external file (preferably from the current users home directory) instead of hardcoding it into this line here. The uid parameter takes the current user id from the environment of the calling user, because depending on who is using my laptop currently (my other household members), he will get this NAS path mounted as himself.

Now before all the autofs magic happens, you have to enable and start the automounter first (if it was a new installation):

$> systemctl enable autofs.service
$> systemctl start autofs.service

One additional note. If you happen to have an older version of FRITZ!OS which supports the SMB 1.0 protocol only, you have to add a ver=1.0 parameter to the above mentioned mount line in /etc/auto.direct.