Block Ads on All Your Devices with a Raspberry Pi

Ads can be one of the internet's more annoying things, and there are few things worse than watching a flash animation for deodorant suck up all your bandwidth. While you have plenty of software solutions to block ads, you can also do it on a deeper level with a Raspberry Pi.

This tutorial will show you how to use your Raspberry Pi as a WiFi access point that blocks ads by default for any devices using it. This is really neat in that it would work for your Android or iOS device, your Xbox 360, TiVo, laptop, and more without needing to customize any of those devices other than to use your Raspberry Pi as the access point for WiFi. Using an ad-blocker can be useful for conserving bandwidth, helping out low-power devices, or for keeping your sanity while browsing the web!

I do suggest whitelisting your favorite ad-supported sites so that you can continue to support them (this tutorial shows how to do this as well).

It's not easy keeping up with those wily ad serving companies so we'll also setup a way to keep your ad blocking lists up to date as part of this tutorial.

This projects turns your Raspberry Pi into a wireless access point, then installs software that makes ads time out. Then, you route your traffic through the Raspberry Pi and that blocks ads on all your devices, from your tablet to your game console. Head over to Adafruit for the full guide

 Rasperry Pi as an access point

Preparation

This tutorial assumes you have your Pi mostly set up and ready to go.

Please follow the tutorials in order to 

• Install the OS on your SD Card  

• Boot the Pi and configure   

Don't forget to change the default password for the 'pi' acccount!

• Setup and test the Ethernet and Wifi Connection

• Setup the Raspberry Pi as an Access Point 

• Connect with a USB Console Cable (optional) 

 When done you should have a Pi that is booting Raspbian, you can connect to with a USB console cable and log into the Pi via the command line interface. Your Pi should also be already setup as a WiFi access point from step 4.

It is possible to do this tutorial via ssh on the Ethernet port or using a console cable.

If using a console cable, even though the diagram on the last step shows powering the Pi via the USB console cable (red wire) we suggest not connecting the red wire and instead powering from the wall adapter. Keep the black, white and green cables connected as is. 

Install Software

 Once you've done all the preparation, setting your Pi up as an ad blocking AP is actually rather simple. The first thing we need to do is install the necessary software, and set it all up.

To start with, uninstall isc-dhcp-server and install dnsmasq. We'll be using dnsmasq as your dhcp server instead of isc-dhcp-server. You may want to do a sudo apt-get update first, and then execute the following: 

 sudo apt-get autoremove isc-dhcp-server 

sudo apt-get install -y dnsmasq dnsutils                                                          

You can test that it installed properly by checking the status:

1. sudo service dnsmasq status

   
   
   
   
   
   
   
   
   
    Create and edit a new file for the dhcp server settings:
   
   
   

   sudo nano /etc/dnsmasq.d/dnsmasq.custom.conf

    Add the following to that file:

   interface=wlan0
   dhcp-range=wlan0,192.168.42.10,192.168.42.50,2h
   # Gateway
   dhcp-option=3,192.168.42.1
   # DNS
   dhcp-option=6,192.168.42.1
   
   dhcp-authoritative
   
   Save the file by typing in Control-X then Y then return
   
   These are the minimum settings required to get the dhcp server setup properly. There are a lot more settings available as examples in /etc/dnsmasq.conf if you want to configure it further.
   
   Any files added to the directory /etc/dnsmasq.d are automatically loaded by dnsmasq after a restart. This is a convenient way to override or add new configuration files in Debian.
   Next, let's update the dns nameservers to route to our pixelserv IP address first. We'll also go ahead and use the google nameservers.
   
   Open the file with sudo nano /etc/resolv.conf and replace the contents with the following: 
   
   

   nameserver 192.168.42.49
   nameserver 8.8.8.8

   nameserver 8.8.4.4 
    After saving the resolv.conf file, let's restart dnsmasq to have the settings take effect: 
   
   

   sudo service dnsmasq restart

    Try testing out the dns by using the dig command. 

    dig adafruit.com

   Your results should be similar to the following: 

   

    Ok, now that we have all of that setup, let's create a script that will 
   redirect known ad servers to an internal IP address.  This will 
   essentially cause any requests to generate an HTTP 404.
   
   Open nano and create a file with the following command:

    
    sudo nano /usr/local/bin/dnsmasq_ad_list.sh 

    Copy and paste the following into the file, and save and exit: 

   #!/bin/bash
   
   ad_list_url="http://pgl.yoyo.org/adservers/serverlist.php?hostformat=dnsmasq&showintro=0&mimetype=plaintext"
   pixelserv_ip="192.168.42.49"
   ad_file="/etc/dnsmasq.d/dnsmasq.adlist.conf"
   temp_ad_file="/etc/dnsmasq.d/dnsmasq.adlist.conf.tmp"
   
   curl $ad_list_url | sed "s/127\.0\.0\.1/$pixelserv_ip/" > $temp_ad_file
   
   if [ -f "$temp_ad_file" ]
   then
   #sed -i -e '/www\.favoritesite\.com/d' $temp_ad_file
   mv $temp_ad_file $ad_file
   else
   echo "Error building the ad list, please try again."
   exit
   fi
   
   service dnsmasq restart
   
   
   Notice, in the above script there is a line starting with "#sed ". You can uncomment that, and modify it to remove your favorite sites from the ad blocking list so you can continue to support them. You can add as many of those lines as you'd like. One example would be:
     sed -i -e '/ads\.stackoverflow\.com/d' $temp_ad_file
    Next allow the file to be executed:
    
   

   sudo chmod +x /usr/local/bin/dnsmasq_ad_list.sh

    Manually run the script to test that it works:

    sudo /usr/local/bin/dnsmasq_ad_list.sh

    You should see the following output:

   

    The above script will need to be run as root in order to properly update
    the configuration file.  Basically, what it does it grab a 
   pre-generated list of known ad server domain names from pgl.yoyo.org and save them to a file in /etc/dnsmasq.d/dnsmasq.adlist.conf.  It then restarts dnsmasq.
   
   You could manually do this every once in a while, but it's easier if we setup a weekly cron job with the root user.
   
   Open crontab with the following command:
       
       sudo crontab -e

    Add the following line to the end of the file and save it:

    @weekly /usr/local/bin/dnsmasq_ad_list.sh

   Congratulations, you should now be blocking ads with your Raspberry Pi. You can test that it's working by executing the following:
   
   

   dig doubleclick.com

   

   And you should see that it gets routed to the 192.168.42.49 IP address:

   One drawback to just stopping here is that we're now timing out on requests that are going to return an HTTP code of 404 for any ad servers. This won't be terribly fast. Another drawback is that any areas with ads will potentially still take up space in the page. We can fix this in the next section.

   
   

   Improving Performance

    One way to improve the performance of the ad blocker is to serve either a 1x1 transparent image, or a blank HTML page. This can be done in a number of ways so we'll show a couple of the options available to you.

   Pixelserv

   The first, and maybe most common is to use pixelserv. This is a really lightweight perl web server that simply serves a 1x1 transparent GIF to any requests made to it. Thus, anytime ads get redirected by dnsmasq to pixelserv, you'll actually receive a tiny image that won't be visible on the page.
   
   To start with, download the pixelserv file: 

   sudo curl -o /usr/local/bin/pixelserv http://proxytunnel.sourceforge.net/files/pixelserv.pl.txt   

    And also change the permissions: 

   
   

   sudo chmod 755 /usr/local/bin/pixelserv

    Now, open the file with nano: 

   sudo nano /usr/local/bin/pixelserv

    You can see that the pixelserv is a fairly small perl script. Let's edit it to change the IP address that we're using (192.168.42.49) to redirect the ads to. Find the line with LocalHost, and change it to the following: 

   
   

   $sock = new IO::Socket::INET (  LocalHost => '192.168.42.49'

    Save the file by typing in Control-X then Y then returnYou could try running the server now, but you'd get the following error:

   pi@raspberrypi /usr/local/bin $ ./pixelserv 

   error : cannot bind : Cannot assign requested address exit

    We can resolve this by adding this IP address to our wlan0 interface (Thanks to this site for this fix!). Open nano and the interfaces file: 

    sudo nano /etc/network/interfaces

    Update your iface wlan0 inet static section to look like the following. We're adding the last two lines (post-up and pre-down): 

    iface wlan0 inet static 

     address 192.168.42.1 

     netmask 255.255.255.0 

     post-up ip addr add dev wlan0 192.168.42.49/24 

     pre-down ip addr del dev wlan0 192.168.42.49/24

    Save the file by typing in Control-X then Y then returnNow reboot your Pi so the settings take effect:

   
   

   sudo reboot

   Once your system comes back up, try running the server. It won't output anything in the console, but you can try refreshing a page you know that has ads that get blocked:

    sudo /usr/local/bin/pixelserv

   It could get annoying having to always run that command. The next logical step would be to create a service that will start the server for us whenever we start our Pi. Let's do that.
   
   First, kill the server you're running by typing "Ctrl-C".
   
   Now, create a new file with nano:

   sudo nano /etc/init.d/pixelserv

   Copy and paste the following to that file:  

   ### BEGIN INIT INFO 

   # Provides: pixelserv 

   # Required-Start: $network 

   # Required-Stop: $network 

   # Default-Start: 2 3 4 5 

   # Default-Stop: 0 1 6 

   # Short-Description: pixelserv server for ad blocking 

   # Description: Server for serving 1x1 pixels 

   ### END INIT INFO 

     

   case "$1" in 

        start) 

           echo "pixelserv: starting" 

           /usr/local/bin/pixelserv & 

           ;; 

       stop) 

           echo "pixelserv: stopping" 

           killall pixelserv 

           ;; 

       *) 

          echo "Usage: service $0 {start|stop}" 

          exit 1 

          ;; 

   esac

     

   exit 0

   Save the file by typing in Control-X then Y then returnChange the permissions on that file: 

   sudo chmod 744 /etc/init.d/pixelserv

   Test that the script works by starting and stopping it: 

     

   sudo /etc/init.d/pixelserv start 

   sudo /etc/init.d/pixelserv stop

   Now, enable the script on startup of your Pi: 

   update-rc.d pixelserv defaults

   You can manually start/stop the pixelserv server by executing the following: 

   sudo service pixelserv start 

   sudo service pixelserv stop

     

   
   

    If you decide you'd rather use the Apache solution, you can disable the pixelserv service on startup: 

   sudo update-rc.d -f pixelserv remove

   Apache

   As an alternative to pixelserv, we can use Apache to serve a blank html file with an HTTP 200 response. Apache is a bit heavier but likely much more stable than pixelserv.
   
   Let's start by installing Apache (make sure to stop and disable pixelserv if you've already installed that): 

   sudo apt-get install apache2 -y

   By default apache is listening to all IP addresses on port 80. You can change this if you like, but it's not necessary.
   
   Test that apache is picking up our redirected requests: 

     

   curl doubleclick.com

   You should get the following:

    pi@raspberrypi ~ $ curl doubleclick.com 

   It works!</h1> 

   This is the default web page for this server.</p> 

   The web server software is running but no content has been added, yet.</p> 

   </body></html> 

   pi@raspberrypi ~ $ 

   That's a bit more than what we want. Let's modify it so we basically just get an OK from apache instead of any content.
   
   First enable the apache2 rewrite engine by executing the following: 

   sudo a2enmod rewrite

   Next, let's update the default VirtualHost. Execute the following to open the default VirtualHost file in nano: 

     

   sudo nano /etc/apache2/sites-available/default

   Edit the section to look like the following (we're adding the last three lines):

     

     /var/www/> 

    Options Indexes FollowSymLinks MultiViews 

    AllowOverride None 

    Order allow,deny 

    allow from all 

    RewriteEngine on 

    RedirectMatch 200 (.*)$ 

    ErrorDocument 200 " "

    

 

Save the file by typing in Control-X then Y then returnMake the same change for the default-ssl file as well (sudo nano /etc/apache2/sites-available/default-ssl).

At this point if you restart Apache, you'll get an error about not being able to determine the server's fully qualified domain name. We can fix that by executing the following command:

echo "ServerName raspberrypi" | sudo tee -a /etc/apache2/conf.d/fqdn

Ok, now we can restart apache: 

sudo service apache2 restart

And test that the response from Apache has changed:

  

pi@raspberrypi /etc/apache2/sites-available $ curl doubleclick.com 

pi@raspberrypi /etc/apache2/sites-available $

That's it, you're all setup for super-speedy ad-blocking from your Raspberry Pi!

FAQ

 

Does this work with SSL traffic?

Yes! This blocks adware and malware sites at the domain (DNS) level, so it will work with HTTPS as well as non-SSL pages

Will this work as a WiFi-to-WiFi bridge? (Or WiFi-to-Cellular)

In theory, if you can get the Access Point setup to work WiFi-to-WiFi then yes the adblocking part will too. However we don't have that part of the tutorial written, and most people get best performance with Ethernet-to-WiFi

HOPE YOU ENJOY THE TUTORIAL