How to mount CIFS shares permanently

Common Internet File System (CIFS) shares are a file-sharing protocol used (mainly) in Windows for accessing files and resources (such as printers) over a network.

Permanently mounting CIFS shares involves configuring your system to automatically connect to these shared resources when the system boots, which is useful when network users need consistent and regular access to them.

In this guide, we will show you how to permanently mount and access CIFS shares. The shares can be hosted on a Windows computer/server, or on a Linux/UNIX server running Samba. If you want to know how to host shares, see Introduction to Samba.

Prerequisites

In order to use this guide, you will need to ensure that your network connections have been configured properly. Throughout this guide, we will use the following naming conventions:

  • The local (Ubuntu) username is ubuntuusername

  • The share username on the Windows computer is msusername

  • The share password on the Windows computer is mspassword

  • The Windows computer’s name is servername (this can be either an IP address or an assigned name)

  • The name of the share is sharename

  • The shares are to be mounted in /media/windowsshare

Install CIFS

To install CIFS, run the following command:

$
sudo apt-get install cifs-utils

Mount unprotected (guest) network folders

First, let’s create the mount directory. You will need a separate directory for each mount:

$
sudo mkdir /media/windowsshare

Then edit your /etc/fstab file (with root privileges) to add this line:

//servername/sharename /media/windowsshare cifs guest,uid=1000 0 0

Where:

  • servername is the server hostname or IP address,

  • guest indicates you don’t need a password to access the share,

  • uid=1000 makes the Linux user (specified by the ID) the owner of the mounted share, allowing them to rename files, and

  • If there is any space in the server path, you need to replace it by \040, for example: //servername/My\040Documents

After you add the entry to /etc/fstab, type:

$
sudo systemctl daemon-reload

And then mount the share:

$
sudo mount /media/windowsshare

Due to the /etc/fstab entry, it will also be automatically mounted at boot time.

Mount password-protected network folders

To auto-mount a password-protected share, we will use a credentials file to avoid storing the password in /etc/fstab, which everyone on the system can read.

Using a text editor, create the file ~/.smbcredentials with the following content:

username=msusername
password=mspassword

And change its permissions to prevent unwanted access to your credentials:

$
chmod 0600 ~/.smbcredentials

Then edit the /etc/fstab file (with root privileges) to add this line:

//servername/sharename /media/windowsshare cifs credentials=/home/ubuntuusername/.smbcredentials 0 0

Run systemctl daemon-reload again:

$
sudo systemctl daemon-reload

Finally, test mounting the share by running:

$
sudo mount /media/windowsshare

If there are no errors, you should test how it works after a reboot. Your remote share should mount automatically. However, if the remote server goes offline, the boot process could present errors because it won’t be possible to mount the share.

Changing the share ownership

If you need to change the owner of a share, you’ll need to add a UID (short for ‘User ID’) or GID (short for ‘Group ID’) parameter to the share’s mount options:

//servername/sharename /media/windowsshare cifs uid=ubuntuusername,credentials=/home/ubuntuusername/.smbcredentials 0 0

Mount network folders with authd

If you use Samba and authd at the same time, you must specify user and group mapping. Otherwise, you will encounter permission issues due to mismatched user and group identifiers.

If you are using Samba with authd, follow the instructions in the steps for the client guide in the authd documentation.

Mount password-protected shares at login time

This method uses the libpam-mount package to mount the network share at login time, using the same password you use to log in to your Ubuntu system. It’s convenient, and arguably more secure, because you don’t have to store your password in a file. But it can only be used if the password for both is the same.

Install libpam-mount

$
sudo apt-get install libpam-mount

Edit /etc/security/pam_mount.conf.xml using your preferred text editor.

$
sudo gedit /etc/security/pam_mount.conf.xml

First, we’re moving the user-specific config parts to a file which users can actually edit themselves.

Remove the commenting tags (<!-- and -->) surrounding the section called <luserconf name=".pam_mount.conf.xml" />. We also need to enable some extra mount options to be used. For that, edit the “<mntoptions allow=...” tag and add uid,gid,dir_mode,credentials to it.

Save the file when done. With this in place, users can create their own ~/.pam_mount.conf.xml.

$
gedit ~/.pam_mount.conf.xml

Add the following:

<?xml version="1.0" encoding="utf-8" ?>

<pam_mount>

<volume options="uid=%(USER),gid=100,dir_mode=0700,nosuid,nodev" user="*" mountpoint="/media/windowsshare" path="sharename" server="servername" fstype="cifs" />

</pam_mount>

Now when the user logs in, the share will be mounted automatically. And when logging out, the share will be unmounted.

Troubleshooting

Login errors

If you get the error “mount error(13) permission denied”, then the server denied your access. Here are the first things to check:

  • Are you using a valid username and password? Does that account really have access to this folder?

  • Do you have blank space in your credentials file? It should be password=mspassword, not password = mspassword.

  • Do you need a domain? For example, if you are told that your username is SALES\sally, then actually your username is sally and your domain is SALES. You can add a domain=SALES line to the ~/.smbcredentials file.

Further reading