A developer has created a DNS filter using a $5 ESP32-C3 microcontroller that blocks over 537,000 domains. This solution offers an efficient and cost-effective method of ad blocking with minimal latency, appealing to users seeking budget-friendly tech solutions.
A developer named ZedAxis has successfully built an ad-blocking DNS filter using an ESP32-C3 "SuperMini" microcontroller. This device, which costs around $5, can handle blocking over 537,000 domains with a latency of just 10 milliseconds.
This project showcases how developers can utilize affordable hardware to create functional network tools without the need for more expensive equipment like Raspberry Pis.
The ESP32-C3, equipped with 400KB of RAM and 4MB of flash storage, was selected due to its capabilities despite being a cost-reduced chip. The memory limitations typically would restrict the storage of large domain lists, but ZedAxis employed a hashing technique to manage this constraint effectively.
By using 40-bit FNV-1a hashes, he minimized collisions while fitting a substantial amount of data into the microcontroller's flash memory. Rather than storing raw domain names, the process includes downloading public blocklists, removing duplicates, hashing the domains, and sorting them for quick lookup.
When a DNS request is made to the ESP32-C3, the system hashes the queried hostname and performs a binary search in its hash table for matches. If a match is found, the request is blocked, promoting efficient use of the device.
This setup serves as a backup to ZedAxis's main ad-blocker, a Raspberry Pi running Pi-hole, ensuring continuous ad filtering even if the primary system is down.
This project highlights the ingenuity within the tech community to repurpose inexpensive components to solve practical problems like ad blocking. It serves as a testament to the potential of microcontrollers in home networking solutions. While lightweight, such projects can inspire similar developments among hobbyists and developers seeking economical tech solutions.
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A developer has created a DNS filter using a $5 ESP32-C3 microcontroller that blocks over 537,000 domains. This solution offers an efficient and cost-effective method of ad blocking with minimal latency, appealing to users seeking budget-friendly tech solutions.