Lightweight Non-Root Firewall and Ad Blocker

RethinkDNS is a powerful, free, and open-source firewall app for Android, helping you block ads and monitor app traffic—no root required. With DNS privacy, customizable blocklists, and real-time reports, RethinkDNS secures your digital life while leaving you in control.

RethinkDNS is built for privacy-focused Android users, giving fine-grained control over which apps can use the internet, block ads and trackers on the device, and customize DNS providers for added security. Instead of relying on root privileges or complicated set-ups, RethinkDNS uses the VPN API and encrypted DNS queries, making it accessible to nearly any Android phone. The app is free and open source, widely used for blocking ads and trackers, bypassing censorship, and safeguarding privacy globally—earning its spot as one of the best firewall apps for Android.

RethinkDNS is engineered on a custom open-source backend, inspired by projects like Pi-hole, OpenSnitch, and WireGuard. The core app is actively maintained on GitHub and receives frequent feature and stability updates. The firewall leverages Android’s VPN API to selectively route DNS and/or network traffic, avoiding performance bottlenecks common to full VPN tunnel apps. Users enjoy DNS-over-HTTPS and DNS-over-TLS for true end-to-end DNS encryption, with easy configuration and fast server-side updates. The development team is active, troubleshooting bugs, optimizing compatibility, and adding new privacy features—making the project a model for committed open-source development in privacy apps.

RethinkDNS encrypts DNS queries to prevent ISPs and middlemen from snooping or manipulating your requests. Over 190 blocklists are available to help block malware, spyware, ads, and trackers—even ones other apps miss. Firewall controls let you block connections while devices are locked, apps are in the background, or specific categories (social, games) are used, putting users in charge of when and how data flows. Real-time connection logs and alerts give an honest look at what’s happening—flagging risky hosts and shady domains. The app remains lightweight on system resources, thanks to efficient routing and selective filtering.

RethinkDNS features some uniquely helpful innovations: users can log network activity per app, block individual domains, and apply custom blocklists on the fly. Advanced features include split-tunneling (routing different apps over different proxies), VPN integrations (WireGuard, SOCKS5), and customizable DNS resolver setups—making it a flexible tool for both casual and advanced Android users. Parents can block adult, gambling, or piracy domains, while business users might block malware, ransomware, or phishing attempts. Bypassing internet censorship is easy, especially in countries with restrictive data practices. The customizable DNS engine is expanding, promising user-crafted privacy solutions.

Like NetGuard, RethinkDNS is a non-root firewall that uses VPN APIs to block traffic and filter DNS requests. While NetGuard is famed for granular network controls (mobile data, roaming, subnet, traffic logging), RethinkDNS adds seamless VPN handover, “block connections without VPN” security, faster encrypted DNS, and the ability to route traffic via WireGuard or multiple proxy types. RethinkDNS firewall configuration guide is robust, giving power users more networking options, while NetGuard excels in simplicity. For blocking ads and trackers without root, both apps are strong, but RethinkDNS’s advanced DNS privacy features stand out for those wanting best-in-class DNS privacy app for Android.