Raspberry Pi Wifi Repeater – Block Ads

Question

I configured my raspberry pi as a wireless repeater (using hostapd and dnsmasq).

Now I wonder how I could use it to block known ad-servers?

What would be the best way? Using iptables? Or setting up an dns-server, which blocks the evil adresses?

Answer 1

If you want a more robust setup, you can try pi-hole. It is an open source software package made to block ads network wide, specifically for a Raspberry Pi. Although it can also run on other platforms. It comes with a management interface and easy updating of the used lists.

Answer 2

I've found a solution and created a script to share it. This script will download a list of known domains and block them by using dnsmasq. Those lists will be updated daily. Run ./adblocker.sh --install|--start|--stop to install, start or stop it.

The script:

#!/bin/bash

installAB () {

  if [[ "$(crontab -l | grep adblocker.sh)" =~ adblocker.sh ]]; then
    echo "adblocker is already installed"
    echo exit
    exit 1
  fi

  crontab -l > mycron
  echo '@daily        SHELL=/bin/bash ~/adblocker.sh --update' >> mycron
  crontab mycron
  rm mycron
  backupFile="/etc/dnsmasq.conf.bak-$(date +%d%m%y%H%M)"
  sudo mv /etc/dnsmasq.conf "$backupFile"
  echo "conf-file=/etc/dnsmasq.domains.conf
addn-hosts=/etc/dnsmasq.hostnames.conf
$(egrep -v  '^#|^s*$' $backupFile)" | sudo tee /etc/dnsmasq.conf > /dev/null

}

updateAB () {

  wget https://raw.githubusercontent.com/notracking/hosts-blocklists/master/domains.txt https://raw.githubusercontent.com/notracking/hosts-blocklists/master/hostnames.txt
  wgetreturn=$?

  sudo mv domains.txt /etc/dnsmasq.domains.conf
  sudo mv hostnames.txt /etc/dnsmasq.hostnames.conf

  if [ $wgetreturn -eq 0 ]; then
      echo "successfully updated: $(date)" >> /home/pi/update_adblocker.log 
  else
      echo "downloading domains and hostnames failed: $(date)" >> /home/pi/update_adblocker.log
  fi

}


activateAB () {

  sudo sed -i '/dnsmasq.domains.conf\|dnsmasq.hostnames.conf/s/^#*//g' /etc/dnsmasq.conf
  echo "adblocker activated"

}


deactivateAB () {

  sudo sed -i '/dnsmasq.domains.conf\|dnsmasq.hostnames.conf/s/^#*/#/g' /etc/dnsmasq.conf
  echo "adblocker deactivated"

}

case "$1" in
  install|--install) 
    updateAB
    installAB
    ;;
  start|--start)
    activateAB
    ;;
  stop|--stop)
    deactivateAB
    ;;
  update|--update) 
    updateAB
    ;;
  *) 
    echo "run the script with »--install«, »--start«, »--stop« or »--update«"
    echo "exit"
    exit 1
    ;;
esac

sudo service dnsmasq restart && echo "service restarted"