DNS-Based Host Blocking for Android

This is a DNS-based host blocker for Android. In the default configuration,several widely-respected host files are used to block ads, malware, and otherweird stuff.

Installing

You can either install it via F-Droid, using the official F-Droid repository, or you can use my personal repository at https://jak-linux.org/fdroid/repo which gets updates ASAP.

You can also download apk files in GitHub's download section. Currently, these are the same files as in my personal F-Droid repository, but that might change in the future.

XDA: Discussions and preview builds

There is a thread at XDA, where DNS66 can be discussed and I occasionaly postpreview builts of the git repository:

https://forum.xda-developers.com/android/apps-games/app-dns66-source-host-ad-blocker-root-t3487497

Using it

On the first start, you must manually update the hosts files (using therefresh button) before the service can work correctly (issue #1); and youmust 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 theentry movable, swipe to either side removes it). For hosts, a later entryoverrides 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 IPv4addresses are not rejected, neither are URLs for DNS server entries (we intendto support URLs in the future, so you can point the app to a remote list ofservers).

How it works

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

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

Privacy Guarantee

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

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

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

2. Debugging. We hope to have a better way to debug program failures thanmanually running logcat. Such a feature by definition requires sharingdebug 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 enableit (it will be disabled by default). No such feature will be turned on withoutyour explicit consent (for example, clicking yes in a dialog asking whether youwant to have automatic updates).

Contributing

See CONTRIBUTING.md

License

This program is free software: you can redistribute it and/or modifyit under the terms of the GNU General Public License as published bythe 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, andsome parts might be licensed under the terms of other compatible licenses. Seethe file copyright for further (machine-readable) information.

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

Code of Conduct

Please note that this project is released with a Contributor Code ofConduct. By participating in this project you agree to abide by its terms.

Authors

Julian Andres Klode jak@jak-linux.org

Parts are derived from https://github.com/dbrodie/AdBuster by Daniel Brodie.