AdAway is an open-source Android ad-blocking application that provides two methods for blocking ads: modifying the system hosts file (requires root) and a local VPN-based DNS filter. The app downloads and manages multiple hosts sources from URLs, parses them into a local Room database, and applies the blocklists either by writing to /etc/hosts or by intercepting DNS queries through a local VPN service. The VPN mode maps real DNS servers to fake addresses, forwards allowed queries, and returns blocked or redirected responses. The architecture follows MVVM with LiveData, ViewModel, and Room, and includes background workers for periodic updates. The app bundles a legacy native C library (tcpdump/libpcap) for packet capture, used for DNS logging. The codebase is actively maintained, with frequent commits and releases, but some native components are outdated and the VPN implementation may have compatibility issues on newer Android versions.