NSupdate bash script

#!/bin/bash

ZONE="johnburch.co.uk"

RECORD="spain"

FQDN="${RECORD}.${ZONE}."

NS="92.27.6.45" # replace with your actual UK server IP or hostname

KEY="/home/john/.bind-ddns.key"

TTL=300

IP_FILE="/var/tmp/current_ip.txt"

CURRENT_IP=$(curl -s https://api.ipify.org)

# Skip update if IP hasn't changed

if [ -f "$IP_FILE" ] && grep -q "$CURRENT_IP" "$IP_FILE"; then

echo "$(date) - IP unchanged: $CURRENT_IP"

exit 0

fi

echo "$(date) - IP changed to $CURRENT_IP, updating..."

# Send dynamic DNS update

nsupdate -k $KEY <<EOF

server $NS

zone $ZONE

update delete $FQDN A

update add $FQDN $TTL A $CURRENT_IP

send

EOF

# Save the new IP

echo "$CURRENT_IP" > "$IP_FILE"

Save this script in /usr/local/bin/update-ddns.sh

Then setup a CRON job

*/5 * * * * /usr/local/bin/update-ddns.sh >> /var/log/ddns.log 2>&1