Self-Hosting Guide: Transmission

If you're torrenting anything sensitive, I highly recommend you use a VPN. Something like mullvad-cli is incredibly simple to use and can be configured to have a "killswitch" or "lockdown mode" to ensure that if the VPN disconnects, your traffic won't be leaked to your ISP.

1. Transmission

Transmission is a cross-platform bittorrent client that supports running a remote control utility, a daemon service for running as a background service, and a command-line client.

Since I love torrenting Linux ISOs and providing them back to the community, let's walk through a tutorial of setting up Transmission on a headless server and connecting it to a domain name (transmission.example.com) so that we can manage our torrents remotely.

This tutorial assumes you have a Linux machine, have Nginx installed, and have a domain name pointing at your Linux machine.

1.1. Installation

First, let's install a couple Transmission packages on the system. We don't need the GUI components, so we'll only install the daemon and command line interface utilities.

sudo apt install transmission-cli transmission-common transmission-daemon

You will need to run the program to initialize the files before you can edit the configurations, so let's run it and end the process.

# Run the program
transmission-daemon -e ~/.local/log/transmission.log
# End the program after it finishes running
transmission-remote --exit

1.2. Configuration

Now that we've run the program for the first time and initialized the relevant files, let's edit those files.

If you edit the files while Transmission is running, your changes won't be saved! Make sure to end the service, update the configuration files, and restart the service.

To start, let's edit the main configuration file.

nano ~/.config/transmission-daemon/settings.json

Within this file, I suggesting skimming every option and determining if you want to change any of those options.

For remote access, we will focus on the following rpc options. This configuration will not require authentication, will allow any device with access (I suggest that you have a firewall restricting access) to access the service ("rpc-bind-access": "0.0.0.0"), will open the service on port 9091, and will whitelist a few LAN IPs ("rpc-whitelist": "127.0.0.1,::1,192.168.0.98,192.168.0.97").

{
    ...
    "rpc-authentication-required": false,
    "rpc-bind-address": "0.0.0.0",
    "rpc-enabled": true,
    "rpc-host-whitelist": "",
    "rpc-host-whitelist-enabled": true,
    "rpc-password": "{7fc02520b97e054f7a15274c7cfafe3cd7330169.OQUAUS4",
    "rpc-port": 9091,
    "rpc-socket-mode": "0750",
    "rpc-url": "/transmission/",
    "rpc-username": "",
    "rpc-whitelist": "127.0.0.1,::1,192.168.0.98,192.168.0.97",
    "rpc-whitelist-enabled": true,
    ...
}

Once you've finished configuring the service, start the service up again.

transmission-daemon -e ~/.local/log/transmission.log

At this point, you should be able to access the website at localhost:9091 (if you're browsing on the machine where Transmission is running) or $server_ip:9091 (if you're browsing from a different LAN device).

If you want to make further changes to Transmission's configuration, I suggest doing so now. Once you start working on remote access via a reverse proxy, you'll be adding an additional layer of complexity that bring in more confusion when errors occur.

NOTE: If you are trying to initialize transmission-daemon via systemd instead of using the manually-executed command above, you may notice that the service will timeout and fail to start.

To fix this timeout issue, you need to edit the service file and change Type=notify to Type=simple.

# Command to edit the service file:
sudo systemctl edit --full transmission-daemon.service
# Make the edit noted above and then reload the service file with this command:
sudo systemctl daemon-reload
sudo systemctl enable transmission-daemon.service
sudo systemctl start transmission-daemon.service

2. Reverse Proxy

Now that the service is running and configured properly, let's work on remote access.

This tutorial will use Nginx, but you can use any reverse proxy or something like Cloudflare Tunnels if that's your thing.

2.1. Configuration

If you have Nginx installed, you should have either the /etc/nginx/conf.d or /etc/nginx/sites-available directories available to create website configuration files. This tutorial assumes the conf.d structure, but it's essentially the same except using the sites-available structure requires you to symlink your files into the sites-enabled directory.

Let's start by creating the website configuration file.

sudo nano /etc/nginx/conf.d/transmission.conf

Within the file, you will need a configuration similar to the code below. Note that this uses SSL and requires a valid TLS/SSL certificate. You can use Let's Encrypt if you don't have a certificate yet.

server {
	listen                  443 ssl;
	listen                  [::]:443 ssl;
	http2			on;
	server_name             transmission.example.com;
	# SSL
	ssl_certificate         /etc/letsencrypt/live/example.com/fullchain.pem;
	ssl_certificate_key     /etc/letsencrypt/live/example.com/privkey.pem;
	ssl_trusted_certificate /etc/letsencrypt/live/example.com/chain.pem;
    # reverse proxy
	location / {
		set $upstream_transmission http://localhost:9091;
		proxy_pass $upstream_transmission;
		proxy_pass_header X-Transmission-Session-Id;
	}
}
# HTTP redirect
server {
	listen      80;
	listen      [::]:80;
	server_name transmission.example.com;
	if ($host ~ ^[^.]+\.example\.com) {
		return 301 https://$host$request_uri;
	}
}

Once you've saved the configuration file, restart the Nginx web server to enable the remote access connection.

sudo systemctl restart nginx.service

At this point, Transmission should now be available at transmission.example.com, same as it's available on the LAN.

Pro Tip: If you dislike something about the website UI, you can edit the website's files in the /usr/share/transmission/public_html/ directory. You can modify the HTML, CSS, and JS files in this directory.

...or, comment on this post on Bubbles!