Wake On LAN Remotely

Created: Jul 05, 2025

Last modified: Jul 06, 2025

You're away from home, you need a file that lives on your desktop PC, and of course the PC is off. Your options: call someone at home and talk them through finding the power button, or give up. This project adds a third one: send a message on Telegram, and the PC turns itself on.

# Waking a PC with a network packet

Most PCs support Wake On LAN (WoL): even when the computer is off, the network card keeps a tiny bit of power and listens to the network. It's waiting for one very specific message, the magic packet, and when it sees it, it turns the computer on.

The packet itself is surprisingly simple: six bytes of FF, followed by the MAC address of the card you want to wake, repeated 16 times, 102 bytes in total. That's it, no password, no handshake.

Why repeat the MAC so many times? Because the card is half asleep: it doesn't really understand network protocols at that point, it just scans incoming data looking for this pattern. A row of FFs followed by the same 6 bytes sixteen times in a row is practically impossible to get by accident, so there's no confusion about who's being woken up.

# The catch: it only works from inside your network

The magic packet is sent as a broadcast, a message to every device on the local network. Routers don't let broadcasts out to the internet (or in from it), so you can't send one from your phone on mobile data. And the PC can't help either: it's off!

So you need a tiny helper that's always on and sits inside your home network. A Raspberry Pi is perfect for the job, and a Telegram bot running on it is the remote control. The whole chain looks like this:

One nice detail: you don't need to open any port on your router. The bot uses polling, which means the Pi is the one that keeps asking Telegram "any new messages for me?". All connections go out of your home, so nothing on the internet can reach the Pi directly.

# What I tried before

This wasn't my first attempt. Here's what didn't quite work, and why:

My brother had the exact same problem, and his feedback helped shape the bot into something anyone can use.

# What you'll need

# Setting it up

1. Clone the repository:

git clone https://github.com/carlosbravo1408/WakeOnLan.git
cd WakeOnLan

2. Create a virtual environment and install the dependencies:

python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt

3. Create a .env file with your settings:

TELEGRAM_TOKEN=1234567890:AnyTeleBotToken
HAS_OTP_VALIDATION=false           # Optional
ISSUER_HANDLER=AlienNerdDev        # Optional

4. Register who can use the bot and which PCs they can wake. The example script generate_user.py shows how to add users (by their Telegram ID), their devices and the MAC addresses of each one.

5. Start the bot:

python main.py

6. Open Telegram, find your bot and send /start. It replies with the list of devices linked to your account; tap one and it wakes up. Behind the scenes, the bot sends the magic packet twice for each MAC address, to ports 7 and 9, because packets on a network can occasionally get lost and it costs nothing to insist.

# Optional: one-time codes (OTP)

Anyone who gets hold of your Telegram account could turn on your PC. If that worries you, enable OTP validation. The first time you use the bot, it sends you a secret and a QR code: scan it with an authenticator app such as Authy or Google Authenticator.

From then on, every time you ask to wake a PC, the bot asks for the current code from the app. And to avoid leaving sensitive things lying around in the chat, those messages delete themselves after a minute.

# Starting the bot automatically

You don't want to log into the Pi and run the bot by hand after every power cut. Instead of a cron job, the clean way on Raspberry Pi OS is a systemd service: it starts the bot on boot and restarts it if it ever crashes.

1. Create a small launcher, main.sh, that activates the virtual environment and runs the bot (replace /path/to/WakeOnLan/ with your actual path):

#!/bin/bash
cd /path/to/WakeOnLan/
source .venv/bin/activate
python main.py

2. Create the service file, WakeOnLan.service, again with your own path:

[Unit]
Description=Wake On Lan Service
DefaultDependencies=no
After=local-fs.target
Requires=local-fs.target

[Service]
Type=simple
Restart=always
RestartSec=10
ExecStart=/bin/bash /path/to/WakeOnLan/main.sh

[Install]
WantedBy=multi-user.target

The key lines are Restart=always and RestartSec=10: if the bot stops for any reason, systemd brings it back ten seconds later.

3. Copy it to /etc/systemd/system, then enable and start it:

sudo cp /path/to/WakeOnLan/WakeOnLan.service /etc/systemd/system

sudo systemctl daemon-reload
sudo systemctl enable WakeOnLan.service
sudo systemctl start WakeOnLan.service

Done: from now on, the bot starts by itself every time the Pi boots.

# And once the PC is on?

Turning it on is only half the job; next you'll want to use it. These are the tools I've tried for that:

# Wrapping up

The core idea here is a classic in networking: when you can't reach something directly, put a small, always-on helper next to it and talk to the helper instead. A 102-byte packet, a Raspberry Pi and a chat bot, and your PC is one message away, wherever you are.