Dynamic DNcS (Dynamic Domain Namecheap System)

About

Dynamic DNcS, or DDNcS, is a very simple Dynamic DNS record updater that works with your Namecheap domain. Many people have written "lite" address-updating programs which either employ a web UI or include a helpful command line menu or work with 20 different services. This isn't any of those. DDNcS is just a simple Python script that does the bare minimum to update your DNS record with Namecheap.

I wrote DDNcS years ago out of frustration with setting up DDclient. I appreciate the hard work that must go into maintaining 5000+ lines of Perl, but getting DDclient set up and playing nicely with systemd has always been just out of reach for me. This is a woe that I recently relived when I performed a fresh OS install on my always-on Raspberry Pi server. Shortly after manually installing the latest version of DDclient, installing all of the Perl dependencies, and running into nothing but trouble with systemd and PID files, I remembered this little bit of code from long ago.

I'm considering updating DDNcS with a simple IP address cache system and the ability to pass a host/IP combo at the command line, but that's it! That's where it'll stop.

Settings

You can configure the program settings by editing the settings.json file. Example settings are provided in the file and should be replaced with your own. The password is not your Namecheap account password. It is the Dynamic DNS password which can be found under the "Advanced DNS" section when you click on the "Manage" button next to your domain. A simple settings.json might look like this:

{
    "hosts": [
        {
            "host": "@",
            "domain": "example.com",
            "ip": "",
            "password": "32CharacterAlphaNumericPassword1"
        }
    ]
}

Executing

Python

The first option for running this script is using your local Python installation. The only thing you need is a currently-supported version of Python.

The script uses only built-in Python libraries, so there's nothing to pip install, no virtual environments to create or maintain, and no potential for typo squatting vulnerabilities on PyPI.

It's as simple as updating settings.json and running python dynamic_dncs.py in the command line.

Docker

If you can't or don't want to install Python, but you do have access to Docker, you can use the included Docker configuration files to set up and run the containers.

Download and create the required Docker assets

docker compose up --detach

Execute the script

docker start dynamic_dncs

Remove the created Docker assets

Note: This does not remove the python:slim image downloaded during setup.

docker compose down

Task Scheduler

It's convenient for me to run DDNcS with a task scheduler. You can use cron, systemd, or just about any other task manager you like.

I prefer to use cron, and I prefer to execute the script once a day and every time my Raspberry Pi restarts. The idea is that if the power goes out, it's likely that my dynamic IP will change and the dynamic DNS address will need to be updated with Namecheap.

To edit your cron configuration file, execute crontab -e in the command line. crontab.guru might be helpful with finding the right configuration for you, but my crontab file might look something like this:

Using local Python installation

# Update DNS on every reboot
@reboot sleep 60; python /path/to/dynamic_dncs.py

# Update DNS every day at 7:00 AM
0 7 * * * python /path/to/dynamic_dncs.py

Using Docker container

# Update DNS on every reboot
@reboot sleep 60; docker start dynamic_dncs

# Update DNS every day at 7:00 AM
0 7 * * * docker start dynamic_dncs

License

This project is licensed under the terms of the MIT license. See LICENSE.md for details.