dhcpd-ddns

A drop-in reimplementation of ISC Kea's DHCP-DDNS server (D2) in Go. It accepts NameChangeRequests (NCRs) from Kea DHCP4/DHCP6 over the same JSON-over-UDP wire format as kea-dhcp-ddns, then applies the DNS updates to a configured backend.

Backends

• RFC 2136 dynamic DNS updates (wire-compatible with Kea D2's dns-servers), with TSIG (incl. digest-bits MAC truncation per RFC 4635) and per-server retry/failover.
• PowerDNS Authoritative HTTP API.
• Technitium DNS Server HTTP API.

Features

• Full RFC 4703 conflict-resolution modes (check-with-dhcid, no-check-with-dhcid, check-exists-with-dhcid, no-check-without-dhcid), with an application-level DHCID ownership store for the HTTP-API backends.
• Durable NCR queue: in-memory, Redis, or SQLite.
• Optional record reaper that removes stale DNS records when leases expire.
• Live configuration reload on SIGHUP (zones, TSIG keys, backends, and listen address) without dropping the queue.

Quick start

# Build (injects version metadata):
just build

# Run with a config file:
./dhcpd-ddns -config /etc/dhcpd-ddns.conf

# Print version:
./dhcpd-ddns -version

With no -config, the daemon runs on built-in defaults (127.0.0.1:53001, in-memory queue) identical to kea-dhcp-ddns.

See examples/ for rfc2136, powerdns, and technitium configurations. The config file is the standard kea-dhcp-ddns DhcpDdns block, plus an optional dhcpd-ddns extensions block for the non-RFC-2136 backends and durable queues.

Installation

Releases ship several formats (see the repository's Releases page):

• Debian/Ubuntu — .deb (amd64/arm64). Installs the binary, a systemd unit, and a default config at /etc/dhcpd-ddns/dhcpd-ddns.conf. Edit it, then systemctl enable --now dhcpd-ddns.

• RHEL/Rocky/EL9 — .rpm (amd64/arm64), same layout.

• OpenBSD — a binary tarball (amd64/arm64); install the binary and run it under your own rc/supervision (there is no native OpenBSD package).

• Nix / NixOS — a flake. Build with nix build github:erestodo/dhcpd-ddns, or use the NixOS module:

  {
    inputs.dhcpd-ddns.url = "git+https://scm.nullnetwork.cc/erestodo/dhcpd-ddns";
    # in your configuration:
    imports = [ dhcpd-ddns.nixosModules.default ];
    services.dhcpd-ddns = {
      enable = true;
      configFile = ./dhcpd-ddns.conf;
    };
  }
  

Container

docker run --rm \
  -p 53001:53001/udp \
  -v /etc/dhcpd-ddns.conf:/etc/dhcpd-ddns.conf:ro \
  scm.nullnetwork.cc/erestodo/dhcpd-ddns:latest

The image is distroless and runs as a nonroot user. Set ip-address to 0.0.0.0 in the config so the listener is reachable from outside the container. Persist the SQLite queue/store with a volume on /var/lib/dhcpd-ddns.

Development

just          # list tasks
just test     # lint + race tests
just fmt      # gofmt

CI (lint, race tests, snapshot build) and releases (multi-arch OCI images + archives) run on Forgejo Actions; see .forgejo/workflows/.

License

MIT — see LICENSE.