qBittorrent is a reliable torrent client for those who prioritize security and efficiency. In this guide, I'll focus on installing qBittorrent-nox—a feature-rich and lightweight version of qBittorrent that doesn't require a graphical environment and can be controlled via a WebUI, making it more suitable for servers. The WebUI interface provides efficient management of qBittorrent through a web browser.

Installation

Let's start the installation of qBittorrent-nox with the command below:

sudo apt install qbittorrent-nox

Creating a Separate System User and Group

To enhance security, qBittorrent-nox should run as an unprivileged user. Creating a systemd service unit facilitates this, as it operates in the background and is initialized on system boot.

Execute the following command to create a user, group, and directory for qBittorrent-nox (for a system user, the directory is not automatically created):

sudo adduser --system --group --home /home/qbittorrent-nox qbittorrent-nox

--system indicates that this is a system user who does not possess all the capabilities of a regular user.
--group creates a group with the same name as the user and adds the user to this group.
--home /home/qbittorrent-nox creates the home directory.

Add Your User to the Group (Optional)

To ensure your account has access to files that qbittorrent-nox will download (for example, if you want to save them in the qbittorrent-nox user's home directory), add yourself to the qbittorrent-nox group:

sudo adduser your-username qbittorrent-nox

Replace your-username with your actual username.

Creating the systemd Service File

Create a new systemd service file to define how the qBittorrent-nox service should operate:

sudo nano /etc/systemd/system/qbittorrent-nox.service

Enter the following content into the file:

[Unit]
Description=qBittorrent Command Line Client
After=network.target

[Service]
Type=forking
User=qbittorrent-nox
Group=qbittorrent-nox
UMask=007
ExecStart=/usr/bin/qbittorrent-nox -d --webui-port=8080
Restart=on-failure

[Install]
WantedBy=multi-user.target

Save and close the file by pressing CTRL+O then CTRL+X.

Reloading systemd daemon

To activate the new service, reload the systemd daemon:

sudo systemctl daemon-reload

IMPORTANT: For older versions of qBittorrent (< 4.6.1), the default username/password is: admin/adminadmin
For newer versions (> 4.6.1) qBittorrent will generate a temporary password and display it in the console, so temporarily change the qbittorrent-nox user's shell to Bash:

sudo usermod --shell /bin/bash qbittorrent-nox

Switch to the qbittorrent-nox user:

sudo -u qbittorrent-nox /bin/bash

Start qbittorrent-nox

qbittorrent-nox

Answer the license agreement question and check your temporary password.

Accessing the Web UI

Access the qBittorrent Web UI via your browser by entering your server's IP address followed by the port number (8080), for example 192.168.1.10:8080

It is extremely important to change the default credentials for security purposes. Go to Tools>Options>Web UI>Authentication in the web interface. Here you can set a custom username and, critically, your own password. This step ensures that your qBittorrent web interface is protected and accessible only to individuals with the correct credentials, and the password will always be the one you set.

After changing the password and saving the settings, return to the console, press Ctrl+C, and our running qbittorrent-nox will close. Now exit the qbittorrent-nox account by executing the command:

exit

Restoring the qbittorrent-nox User's Shell to a Secure State

This is a very important step! Always return the system user's shell to a secure state to prevent unauthorized interactive login:

sudo usermod --shell /usr/sbin/nologin qbittorrent-nox

Starting and Enabling

Now start the qBittorrent-nox service and enable it to start on boot:

sudo systemctl enable qbittorrent-nox

sudo systemctl start qbittorrent-nox

It is recommended to check the status to ensure the service is running:

systemctl status qbittorrent-nox

That's all. I hope the article was helpful. If you have any questions or recommendations, I'll be glad to see them in the comments.