It was yesterday that Linus’ tech channel video kindly introduced me the idea of a Pi-hole. It’s a Raspberry Pi -based gadget that makes web surfing less painful, by removing a lot of the ads present in apps and web pages.

• power switch
• UPS backup power from 9V battery or similar, if required for graceful shutdown
• a physical case
• SD card of sufficient size (to hold future blacklist + whitelist data)
• rather minimal software footprint apart from the required
• remote connection daemon (ssh?) running on the device
• web interface for configuration (comes with standard Pi-hole)

What does the Pi-hole do?

Serving you almost ad-free Internet at home or office. Pi-hole is a very small embedded computer, readily available as Raspberry Pi devices. After a software install, there’ll be a dashboard (GUI) and some server software that will do the magic.

The promise is that by configuring your tablets, phones and PCs to use the IP address of Pi-hole instead of the ordinary public DNS server (given to us usually by Wifi connection automatically), you can save yourself the headache of watching countless ads during the day.

Pi-hole runs on Raspberry Pi; it can run on any embedded Linux OS, that supports certain key factors necessary: a network stack for TCP/IP, and a way for the device to be a middleman in Internet traffic.

The device has software: an ordinary DNS server daemon, which has been modified to consult both a whitelist and a blacklist. Whitelist means internet addresses that are accepted by you, the user. Blacklist is typically downloaded from a main repository which curates known aggressive ad distribution servers.

When a computer, tablet or phone’s web browser asks for content via a DNS query, the request goes through Pi-hole device first (Pi-hole has typically a static IP address so technically it is always there, ready to respond, when computers use DNS). Pi-hole checks the request against its whitelist and blacklist. If an address is on whitelist, it gets passed to real DNS server from the other network interface. If the address is on a blacklist, then it means that ads would be served, and Pi-hole simply reports (fakes the answer) that the server is “missing”.