Pi-hole

Probably the best known representative of the free advertising blockers is Pi-hole [1]. The installation wizard is straightforward and can be used by Linux newcomers. After a short question and answer session, the installer leaves a preconfigured ad filter and links to the local website for administration and evaluation. Finished now at the command line, the user does the rest from a web page. With the use of preset blacklists, Pi-hole automatically loads almost 125,000 entries into its DNS service and starts working.

Pi-hole was designed for the Raspberry Pi, but it also runs on other SBCs or as a virtual machine. Even in large environments, the service cuts a fine figure. In a field test, it ran on a corporate network with about 1,200 clients without any performance losses or downtime.

Pi-hole's evaluation feature provides statistics in real time. The graphs in Figure 1 show the DNS load of all clients within a 24-hour period and the top 10 allowed and blocked websites.

Figure 1: What is allowed and what isn't? Pi-hole knows which websites were most frequently requested and blocked.

Synopsis

The well-documented Pi-hole is easy to install, and it works immediately. With only a few possible tweaks, it is therefore suitable for newcomers. As of recently, it can handle different clients differently and provide individual end devices (e.g., smartphones for minors) special protection.

AdGuard Home

AdGuard Software Limited began developing ad blockers for web browsers [2] and then expanded its concept with AdGuard Home [3] to include network-based blockers. The software does not prefer any particular hardware and is suitable for all SBCs that come with Linux or BSD. Additionally, the ad blocker can run piggyback on an existing firewall.

When AdGuard Home is started in the console for the first time, the command output points to a local web address. The web interface guides the user through further configuration. After the last step, AdGuard is ready for use and runs as a DNS server with an active blacklist. Up to this point, AdGuard is hardly different from Pi-hole. However, the preset blacklists prove to be a little bit gappy for non-English markets. Language add-ons in the form of EasyList [4] are recommended.

AdGuard Home does not treat all clients equally and can handle certain end devices separately to exclude individual clients or IP ranges from adult content or to force safe search (Figure 2). Additionally, AdGuard Home blocks services such as Steam, Netflix, and Skype – either per client or for all clients.

Figure 2: AdGuard Home treats its clients individually, if desired.