Simple DDNS updater for noip.com - Checks your real IP first before sending update.

noip-ddns-update.sh

#!/bin/bash

# Configuration variables
USERNAME="your_username"
PASSWORD="your_password"
HOSTNAME="mytest.example.com"

# Path to required binaries
CURL="/usr/bin/curl"
DIG="/usr/bin/dig"

# Get current external IP address from kodelatte.com
CURRENT_IP=$($CURL -s https://kodelatte.com/)

# Check if we got a valid IP address
if [[ ! $CURRENT_IP =~ ^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
  echo "Error: Could not retrieve a valid IP address from kodelatte.com"
  exit 1
fi

echo "Current external IP: $CURRENT_IP"

# Get the current DNS record for the hostname
DNS_IP=$($DIG +short "$HOSTNAME" A | grep -v "\.$" | head -n 1)

if [ -z "$DNS_IP" ]; then
  echo "No DNS record found for $HOSTNAME or dig command failed"
  echo "Proceeding with update..."
elif [ "$DNS_IP" == "$CURRENT_IP" ]; then
  echo "DNS record is already up to date ($DNS_IP). No update needed."
  exit 0
else
  echo "DNS record ($DNS_IP) differs from current IP ($CURRENT_IP). Update needed."
fi

# Construct the update URL
UPDATE_URL="http://$USERNAME:[email protected]/nic/update?hostname=$HOSTNAME&myip=$CURRENT_IP"

# Send the update request
echo "Sending DNS update request..."
RESPONSE=$($CURL -s "$UPDATE_URL")

# Display the response
echo "Response: $RESPONSE"

# Check response for common status codes
if [[ "$RESPONSE" == "good"* ]]; then
  echo "Update successful! IP address has been updated."
elif [[ "$RESPONSE" == "nochg"* ]]; then
  echo "No change needed. Your IP address is already up to date."
elif [[ "$RESPONSE" == "nohost" ]]; then
  echo "Error: Hostname does not exist."
elif [[ "$RESPONSE" == "badauth" ]]; then
  echo "Error: Invalid username or password."
elif [[ "$RESPONSE" == "abuse" ]]; then
  echo "Error: Abuse detected. Your account has been blocked."
else
  echo "Unrecognized response. Please check the documentation for more information."
fi