dhcpd-lease-dns

dhcpd-lease-dns is a DNS server that reads OpenBSD dhcpd dhcpd.leases file and answers DNS querys on the lease entries.

On startup, it executes tail -f dhcpd.leases, starts the DNS server. On OpenBSD, it pledges "stdio inet proc".

Building

dhcpd-lease-dns is a simple go program. It can simply be built with

go build

Cross compiling for OpenBSD on any go platform:

GOOS=openbsd go build

; Windows (untested)
set GOOS=openbsd
go build

Commandline

Usage of ./dhcpd-lease-dns:
-dhcpd-leases   string dhcpd leases file (default "/var/db/dhcpd.leases")
-dns-port       int    DNS UDP port (default 5333)
-domain         string local domain for replies (default "dhcp.local")

-daemon                daemonize process
-daemon.chroot  string chroot directory
-daemon.pidfile string pid file name
-daemon.syslog         log to syslog (default true)

-quiet                 quiet normal logging
-debug                 debug logging
-license               show license
-readme                show Readme.md

Configure as daemon on OpenBSD

/etc/rc.d/dhcpddns

#!/bin/ksh

daemon="/usr/local/sbin/dhcpd-lease-dns -daemon"
daemon_user="nobody"

. /etc/rc.d/rc.subr

rc_reload=NO

rc_cmd $1

/etc/rc.conf.local

pkg_scripts=dhcpddns
dhcpddns_flags=-domain=dhcp.my.domain

Stub-Zone in unbound

/var/unbound/etc/unbound.conf

server:
    local-zone: "dhcp.my.domain" transparent
    local-zone: "168.192.in-addr.arpa" transparent
    # do-not-query-localhost: no # needed if stub-addr is localhost

stub-zone:
    name: "dhcp.my.domain."
    stub-addr: 192.168.123.123@5333

stub-zone:                                                                                                                                                    
    name: "168.192.in-addr.arpa."                                                                                                                          
    stub-addr: 192.168.123.123@5333