walldns(8)

📦 version 1.05, in debian bookworm, debian trixie, nixos 26.05, nixpkgs unstable, ubuntu jammy, ubuntu noble, ubuntu questing, ubuntu resolute, ubuntu stonking

💖 NAME 💖

okay bestie, gather round, because walldns is literally a reverse DNS wall and she is serving looks and privacy simultaneously 💅

🎀 DESCRIPTION 🎀

so walldns is a reverse DNS wall, periodt. she accepts iterative DNS queries for in-addr.arpa domains from hosts alllll around the Internet 🌍, and she hands back generic responses that avoid revealing local host information. like, she's not gonna spill the tea about your actual machines, no cap 🙈

for example, walldns provides a PTR record for 4.3.2.1.in-addr.arpa showing 4.3.2.1.in-addr.arpa as the name of IP address 1.2.3.4, and a matching A record showing 1.2.3.4 as the IP address of 4.3.2.1.in-addr.arpa. the way that it just mirrors everything back 💫 iconic behaviour honestly.

✨ Configuration ✨

normally walldns is set up by the walldns-conf(8) program. let that queen do her thing 🫶

walldns runs chrooted in the directory specified by the $ROOT environment variable, under the uid and gid specified by the $UID and $GID environment variables. so yeah, she's cozy in her little jail, living her best contained life 🏠✨

walldns listens for incoming UDP packets addressed to port 53 of $IP. and bestie, listen — she does not listen for TCP queries. UDP only, she's picky like that 💅

🦋 Further details 🦋

walldns is a bouncer at the club, fr fr. she rejects:

  • inverse queries
  • non-Internet-class queries
  • truncated packets
  • packets that contain anything other than a single question
  • queries for domains outside in-addr.arpa
  • request types other than A, PTR, and *

no fake IDs, no drama, no entry 🚫🎟️

walldns does not include NS or SOA records with its responses. she keeps it minimal, she keeps it mysterious 💀

walldns uses TTLs slightly over one week. lowkey generous with the cache time, highkey keeping it simple 🌸

🌈 SEE ALSO 🌈

and that's the whole vibe, bestie 💖 this lil masterpiece came to you from the System Manager's Manual — the walldns(8) page, no date attached, just pure timeless energy 👑✨ go forth and wall those reverse DNS queries 🧚⭐

📦 where this page comes from