rbldns(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 💖

rbldns — an IP-address-listing DNS server, bestie. that's the whole vibe. 🦋

🌸 DESCRIPTION 🌸

okay so picture this: rbldns is literally an IP-address-listing DNS server. she sits there, cute and unbothered, accepting iterative DNS queries from hosts all over the Internet that roll up asking about various IP addresses. 🫶

and what does she do with those questions? she sends back responses showing whether those addresses are on a locally configured list — like an RBL or a DUL. that's it, that's the job, and she ate. 💅

🎀 Configuration 🎀

ngl, normally you don't even set rbldns up by hand — the rbldns-conf(8) program does it for you. iconic delegation, honestly. ✨

here's the rundown, no cap:

  • rbldns runs chrooted in the directory specified by the $ROOT environment variable, under the uid and gid specified by the $UID and $GID environment variables. she's cozy in there, she's contained, she's thriving. 🧚
  • rbldns listens for incoming UDP packets addressed to port 53 of $IP. and listen — she does not listen for TCP queries. not a single one. don't come at her with TCP, she will not answer. 💀
  • rbldns handles domains of the form d.c.b.a.base, where a.b.c.d is the IP address in question and base is given by the $BASE environment variable. read it backwards, it's giving reverse-IP realness. 🔥

now for the ✨ rejection era ✨ — rbldns says no to:

  • inverse queries
  • non-Internet-class queries
  • truncated packets
  • packets that contain anything other than a single query
  • query types other than A, TXT, or *
  • queries for domains outside $BASE
she is booked and busy, okay? one query per packet, correct class, inside $BASE, or it's a no. 💅

and for everything else that does pass the vibe check? she looks those other queries up inside data.cdb, a binary file created by rbldns-data(8). 🍓

👑 SEE ALSO 👑

that's the whole page, bestie — straight out of the System Manager's Manual, section rbldns(8). go forth and answer those queries responsibly. mwah. 💖✨🎀

📦 where this page comes from