Section 1.1: Why Use a Raspberry Pi Zero W?

Utilizing the Raspberry Pi Zero W as a Tor modem is an innovative way to enhance your privacy online. By routing all traffic through Tor, you can achieve a higher level of anonymity. I have previously provided guides on setting up Tor access points and proxies, but the lightweight nature of the Pi Zero W makes this project particularly appealing.

Section 1.2: Setting Up Your Raspberry Pi

Begin by flashing your Micro SD Card with Raspbian Lite. To enable SSH, create an empty file named ssh in the boot directory. Next, modify config.txt to include dtoverlay=dwc2, and update cmdline.txt to append modules-load=dwc2,g_ether after rootwait. If you're unfamiliar with this process, Circuit Basics offers a detailed guide.

To connect your Pi to your WiFi network automatically, create a wpa_supplicant.conf file in the boot directory with the following configuration:

country=US # Your 2-digit country code

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev

network={

ssid="YOUR_NETWORK_NAME"

psk="YOUR_PASSWORD"

key_mgmt=WPA-PSK

}

After inserting the SD Card into your Pi, SSH into your device and run raspi-config to adjust localization settings, GPU memory, and to expand the file system. Reboot your device afterward.

Next, set up NTP by editing the configuration file:

sudo nano /etc/systemd/timesyncd.conf

Uncomment the second line, specify your preferred NTP server (like time.cloudflare.com), and ensure synchronization is enabled:

sudo timedatectl set-ntp true

Check your configuration with:

timedatectl status

Update your system and install necessary packages while saving the current IPv4 and IPv6 rules:

sudo apt-get update && sudo apt-get upgrade -y

sudo apt install dnsmasq iptables-persistent tor dnsutils -y

Configure a static IP address for usb0 by editing the dhcpcd.conf file:

sudo nano /etc/dhcpcd.conf

Add the following lines at the end of the file:

interface usb0

static ip_address=192.168.1.1/24

Now, set up a DHCP server with DNSMASQ to allocate an IP address on usb0 for client computers. Edit the dnsmasq.conf file:

sudo nano /etc/dnsmasq.conf

Insert these lines at the end of the file:

interface=usb0

dhcp-range=192.168.1.11,192.168.1.30,255.255.255.0,24h

Next, we will configure Tor to act as a translation service and enable proxy access for the Tor Browser through the USB modem. First, back up the torrc file:

sudo cp /etc/tor/torrc /etc/tor/torrc.backup

Then, edit the torrc file:

sudo nano /etc/tor/torrc

Uncomment and add the following configurations:

SocksPort 192.168.1.1:9050

SocksPolicy accept 192.168.0.0/16

Log notice file /var/log/tor/notices.log

RunAsDaemon 1

VirtualAddrNetwork 10.192.0.0/10

AutomapHostsSuffixes .onion,.exit

AutomapHostsOnResolve 1

TransPort 192.168.1.1:9040

DNSPort 192.168.1.1:53

Save your changes and create the Tor log file:

sudo touch /var/log/tor/notices.log

sudo chown debian-tor /var/log/tor/notices.log

sudo chmod 644 /var/log/tor/notices.log

Enable the Tor service:

sudo update-rc.d tor enable

Next, configure IPTABLES:

sudo iptables -F

sudo iptables -t nat -F

Set up routing to share your WiFi connection (wlan0) through usb0:

sudo iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE

sudo iptables -A FORWARD -i wlan0 -o usb0 -m state --state RELATED,ESTABLISHED -j ACCEPT

sudo iptables -A FORWARD -i usb0 -o wlan0 -j ACCEPT

Block SSH connections from WiFi:

sudo iptables -A INPUT -i wlan0 -p tcp --dport 22 -j DROP

Allow SSH, DNS, Tor proxy, and route TCP traffic over Tor from usb0:

sudo iptables -t nat -A PREROUTING -i usb0 -p tcp --dport 22 -j REDIRECT --to-ports 22

sudo iptables -t nat -A PREROUTING -i usb0 -p udp --dport 53 -j REDIRECT --to-ports 53

sudo iptables -t nat -A PREROUTING -i usb0 -p tcp --dport 9050 -j REDIRECT --to-ports 9050

sudo iptables -t nat -A PREROUTING -i usb0 -p tcp --syn -j REDIRECT --to-ports 9040

Save the running IPTABLES configuration:

sudo sh -c "iptables-save > /etc/iptables/rules.v4"

sudo sh -c "iptables-save > /etc/iptables.ipv4.nat"

Enable Network Forwarding:

sudo nano /etc/sysctl.conf

Uncomment the following line to enable packet forwarding:

net.ipv4.ip_forward=1

Update your local DNS settings:

sudo nano /etc/resolv.conf

Set nameservers to 1.1.1.1 or another public DNS provider.

Reboot the Raspberry Pi. After restarting, check your network adapter to see if you have an IP within the DHCP range. Disable the WiFi connection and test if Tor is functioning properly.