The definitive guide to protecting your home network from cyber threats with a Raspberry Pi
Dedicated antivirus tools may not be mandatory these days, but that doesn’t mean the Internet is free from the scourge of viruses. Rather, with how ubiquitous computing devices have become over the last couple of years, there's a truckload of spyware, keyloggers, and other malware floating online, ready to target their next victim.
Thankfully, there are just as many ways to protect all the devices connected to your home network. In fact, if you have a spare Raspberry Pi board, you can easily convert it into a network monitoring tool to prevent malware from causing harm to the devices connected to your home network.
Although we’ll be installing quite a few applications, everything besides the optional section of this project can be replicated on your average Raspberry Pi. I used the 8GB variant of the Raspberry Pi 5 in the tutorial, but other boards, including the less powerful RPi Zero W series, should work fine as well. However, you’ll need more storage than usual, and I recommend getting a microSD card with a minimum storage capacity of 16GB to avoid running out of space in the middle of installing the apps.
Next, we’ll assume you’ve already installed an operating system on the microSD card. I had planned to go with Kali Linux because it’s the crème de la crème OS for anything and everything related to cyber security. However, I finally chose the Raspberry Pi OS due to its better performance and beginner-friendly nature, though you can use Kali Linux or a Debian-based distro.
Nmap is a fantastic probing tool that lets you scan all the devices connected to your home network and run commands to detect vulnerabilities that can be used to execute harmful payloads. You can install it on your Raspberry Pi by following these steps.
sudo apt install snapd -y
sudo snap install snapd
sudo snap install nmap
sudo snap connect nmap:network-control
Once you’ve installed Nmap, you can run several scripts to diagnose security vulnerabilities in your devices and website. Here are some common commands that you should remember:
nmap IP_address
nmap URL
nmap -sV --script vulners IP_address
Besides these three commands, Nmap has different flags and options for all your network diagnostic needs. You can browse them by typing nmap into the terminal.
For the uninitiated, packet sniffing is a technique that can intercept the data packets transmitted to and from your devices. This lets you analyze the traffic to ensure your data isn’t getting routed to an unauthorized party. We’ll use Wireshark to bring packet sniffing capabilities to our Raspberry Pi.
sudo apt install wireshark -y
sudo chmod a+x /usr/bin/dumpcap
With that, you’re free to use Wireshark to analyze the network traffic on Ethernet, Wi-Fi, and other connections.
VPN, or Virtual Private Network, is a privacy-driven tool that conceals your public IP address to maintain anonymity on the Internet. If you’re not fond of third-party VPN providers, you should check out the PiVPN utility, which lets you create an OpenVPN/WireGuard server on your Raspberry Pi.
We already have a dedicated article on how to set up PiVPN on the Raspberry Pi, but here’s a short version of the procedure:
curl -L https://install.pivpn.io | bash
All the tools I’ve mentioned so far can be installed on a single Raspberry Pi, and you won’t have any issues running them simultaneously. However, you’ll need to flash the Raspberry Pi with the OpenWRT firmware to use the SBC as a network-wide firewall.
As such, you’ll need a second Raspberry Pi for this procedure. And not just any board, mind you. Since OpenWRT’s UI can only be accessed once you’ve connected the SBC to both your PC and router, you can’t use a Raspberry Pi model that lacks a dedicated Ethernet port. You’ll also need a USB Type-A-to-Ethernet adapter to pair the SBC with your router.
Like the VPN, we have a detailed guide to help you with setting up the Raspberry Pi-flavored firewall. But here's a quick overview of the entire process:
http://192.168.1.1/
Those are some methods even beginners can use to safeguard their home networks from cyber threats. If you’re completely new to SBCs or networking, you can spend some time getting your bearings with Nmap and Wireshark. They’re quite easy to use and work incredibly well at flushing out suspicious activities on your home network.
Once you’ve gained more experience, I recommend giving the OpenWRT-powered firewall a shot. Although it’s a rather cumbersome project that can make a real mess out of your desk, a properly configured Raspberry Pi firewall can eradicate all the threats targeting your home network!