Lightweight, robust, and zero-dependency scripts to automatically update your dynamic IP address for DuckDNS.

This repository contains two scripts tailored for different environments:

1. Windows: A modern PowerShell (7.6+) script utilizing Invoke-RestMethod and the built-in Task Scheduler.
2. Linux / OpenWrt / Embedded: A strict POSIX-compliant sh script relying on curl or wget and standard cron.

Both scripts feature built-in installation logic, meaning they can set themselves up to run silently in the background every 5 minutes with full logging capabilities.

Before running or installing either script, you MUST edit the files and replace the placeholder values with your actual DuckDNS details.

Open the scripts in a text editor and locate these exact lines at the top:

In both duckdns.ps1 and duckdns.sh: Change "CHANGE_ME" to your actual DuckDNS subdomain, and "CHANGE_ME_TO" to your private DuckDNS token.

DOMAIN="CHANGE_ME"       <-- e.g., "mycustomdomain" (without .duckdns.org)
TOKEN="CHANGE_ME_TO"     <-- e.g., "a1b2c3d4-..."

(Alternatively, both scripts support passing these values as command-line arguments if you prefer not to hardcode them).

Requirements: PowerShell 7.6+ (pwsh.exe).

To test the script and update your IP immediately, simply run it:

.\duckdns.ps1

To install the script so it runs silently in the background every 5 minutes regardless of who is logged in:

1. Open PowerShell as Administrator.
2. Run the script with the -Install switch:

.\duckdns.ps1 -Install

This will create a hidden Scheduled Task running as the SYSTEM account. Logs are written to C:\ddns.log.txt by default.

You can override the hardcoded variables on the fly:

.\duckdns.ps1 -Domain "anotherdomain" -Token "your-token-here" -LogPath "D:\Logs\duckdns.txt"

Requirements: curl or wget, and cron (Standard on almost all Linux/OpenWrt distributions).

Make the script executable:

chmod +x ./duckdns.sh

Run the script to update the IP and view the output directly in the terminal:

./duckdns.sh

To install the script into the current user's crontab to run every 5 minutes:

./duckdns.sh --install

(Note: If you want the log file to be saved in /var/log/ddns.log, you must run the installation with sudo, otherwise it will warn you about missing write permissions).

To safely remove the script from your crontab:

./duckdns.sh --uninstall

The bash script accepts standard flags to override the internal variables:

./duckdns.sh --domain "anotherdomain" --token "your-token-here" --log "/tmp/custom_log.txt"

• Author: Andreas Nilsen (adde88@gmail.com)
• GitHub: adde88
• Copyright: © 2026