Created
May 15, 2025 18:11
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#!/bin/sh | |
# to use: | |
# write me to /usr/local/bin/dnsmasq-nsupdate.sh | |
# chmod +x /usr/local/bin/dnsmasq-nsupdate.sh | |
# append to /etc/dnsmasq.conf: | |
# dhcp-script=/usr/local/bin/dnsmasq-nsupdate.sh | |
# in /etc/init.d/dnsmasq, find the blob of lines that begin "procd_add_jail_mount" and add: | |
# procd_add_jail_mount /usr/local/bin/dnsmasq-nsupdate.sh /usr/bin/logger /usr/bin/nsupdate /lib /usr/lib /etc/dnsmasq-nsupdate | |
# restart dnsmasq | |
# Borrowed from https://askubuntu.com/questions/557098/bash-command-to-convert-ip-addresses-into-their-reverse-form | |
reverseip () { | |
local IFS | |
IFS=. | |
set -- $1 | |
echo $4.$3.$2.$1 | |
} | |
# Add, old, or del, determines mode | |
AOD=$1 | |
# Mac address of the lease | |
MAC=$2 | |
# New IP address | |
IP_ADDR=$3 | |
RIP=$(reverseip $3) | |
# Hostname | |
L_HOSTNAME=$4 | |
FQDN=${L_HOSTNAME}.${DNSMASQ_DOMAIN} | |
TTL="3600" | |
KEYFILE=/etc/dnsmasq-nsupdate/keyfile.key | |
if [ $AOD == "add" ] || [ $AOD == "old" ] | |
then | |
echo " | |
update delete ${FQDN} A | |
update add ${FQDN} ${TTL} A ${IP_ADDR} | |
update delete ${RIP}.in-addr.arpa. PTR | |
update add ${RIP}.in-addr.arpa. $TTL PTR ${FQDN} | |
send | |
" | nsupdate -k $KEYFILE | logger -t dnsmasq-nsupdate | |
else | |
# clear old addresses only | |
echo " | |
update delete ${FQDN} A | |
update delete ${RIP}.in-addr.arpa. PTR | |
send | |
" | nsupdate -k $KEYFILE | logger -t dnsmasq-nsupdate | |
fi |
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