DNS-Based Ad Blocking for Android

This is a DNS based ad blocker for Android.

Get it on F-Droid

Using it

On the first start, you must manually update the hosts files (using the refresh button) before the service can work correctly (issue #1); and you must also update the hosts files yourself regularly for now (issue #2).

Items in the hosts and DNS servers lists can be moved around and removed) of the list using standard RecyclerView interactions (long press makes the entry movable, swipe to either side removes it). For hosts, a later entry overrides a previous entry; for DNS servers, the first server is preferred.

Currently, there are some minor usability issues:

  • If you change a setting, you must manually restart the vpn service (issue #3)
  • IPv6 servers are not supported (issue #4)

There's also no validation of input, so DNS servers that are not valid IPv4 addresses are not rejected, neither are URLs for DNS server entries (we intend to support URLs in the future, so you can point the app to a remote list of servers).

How it works

The app establishes a VPN service, with routes for all DNS servers diverted to it. The VPN service then intercepts the packages for the servers and forwards any DNS queries that are not blacklisted.

Custom upstream DNS can be configured. If the feature is turned off, the current connection's DNS servers are used. The app ships are pre-defined list of well known (mostly German) non-logging servers courtesy of the Chaos Computer Club.

Privacy Guarantee

Privacy is the most important aspect of DNS66. Currently, DNS66 is strictly data reducing: Running it can only reduce the amount of data leaving your device, not increase it (except for fetching hosts files, obviously), as for each request, we will either allow it to leave your device or not - we will not send other requests or add other information to the request.

While not yet implemented, future versions of DNS66 might have additional features that might share more data than your phone normally would. Among these features are:

  1. Automatic updates. Your phone might periodically contact servers to query for new upstream versions and new host lists. DNS66 will only include as much data as necessary to complete the request.

  2. Debugging. We hope to have a better way to debug program failures than manually running logcat. Such a feature by definition requires sharing debug logs. Debug logs (including logcat) may include personal information, and you should review them before sharing them publicly.

If such a feature is added, you will be presented with the choice to enable it (it will be disabled by default). No such feature will be turned on without your explicit consent (for example, clicking yes in a dialog asking whether you want to have automatic updates).




This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

Parts of the program are licensed under only version 3 of the license, and some parts might be licensed under the terms of other compatible licenses. See the file copyright for further (machine-readable) information.

Binaries also bundle external libraries. To the best of our knowledge those are licensed under the Apache license, version 2.0, except for pcap4j, which is licensed under the MIT license, and dnsjava, which uses a 3 clause BSD license. See the file copyright.libraries for further (machine-readable) information.


Julian Andres Klode

Parts are derived from by Daniel Brodie.