How To Automatically Remount CIFS on Network Reconnect in Ubuntu

In this article, we’ll delve into the process of setting up your Ubuntu system to automatically remount a CIFS (Common Internet File System) network share whenever your network reconnects. This is particularly useful in scenarios where your network connection is unstable or if you’re frequently switching between different networks.

Understanding CIFS

CIFS is a network file system protocol that allows systems to share files and resources, such as printers. It’s a version of SMB (Server Message Block) and is commonly used in Windows networks, but it can also be used on Linux systems like Ubuntu.

Prerequisites

Before we proceed, ensure that you have:

• A working Ubuntu system
• Root or sudo access
• A configured CIFS network share

Method 1: Using Systemd Automount

Systemd, an init system used in Linux distributions to bootstrap the user space and manage all processes subsequently, offers an automount feature which can be utilized for our purpose.

Step 1: Modify the fstab Entry

Open your /etc/fstab file with a text editor of your choice (we’ll use nano):

sudo nano /etc/fstab

Add the following options to your fstab entry for the network share: noauto,x-systemd.automount,x-systemd.idle-timeout=30. Here’s what they do:

• noauto: Prevents the share from being mounted at boot.
• x-systemd.automount: Mounts the share when it’s accessed.
• x-systemd.idle-timeout=30: Unmounts the share if there’s no activity for more than 30 seconds.

Step 2: Reload Systemd and Restart the Remote-fs.target

After modifying the fstab file, run the following commands to reload systemd and restart the remote-fs.target:

sudo systemctl daemon-reload
sudo systemctl restart remote-fs.target

Method 2: Using a Script Triggered by Network Events

Another approach is to use a script that will be triggered upon network events.

Step 1: Create the Script

Create a script in /etc/network/if-up.d/ (for instance, /etc/network/if-up.d/mount-share) that will be executed upon connecting to the network.

Here’s a simple script that checks if the network is the desired one (by checking the SSID) and then runs the mount -a command to mount all entries in /etc/fstab:

#!/bin/sh
if [ "$IFACE" = "eth0" ]; then
 mount -a
fi

This script checks if the interface ($IFACE) is eth0 (replace with your network interface if different) and if so, runs mount -a.

Step 2: Make the Script Executable

After creating the script, make it executable using the following command:

sudo chmod +x /etc/network/if-up.d/mount-share

Conclusion

In this article, we’ve explored two methods to automatically remount a CIFS network share upon network reconnection in Ubuntu. Both methods have their own advantages: the systemd method is simpler and requires less scripting knowledge, while the script method offers more flexibility and can be customized to suit your specific needs.

Remember to test your setup thoroughly to ensure that the network share is remounted as expected after a network reconnection. If you encounter any issues, check your system logs and fstab file for potential errors.