update-ddns

This program checks for IPv6/v4 addresses changes, and updates the linked domains accordingly.
You don't need to install a separate DDNS client on each of your IPv6 machines anymore.

Getting started

Start by cloning the repository:

git clone https://github.com/Mathis-6/update-ddns.git

Move the config.json outside of the repository to prevent git pulls overwriting the config

Install the dependencies:

pip install -r requirements.txt

Configuring

All the configuration is stored in config.json
Change the values depending on your environment.

update_delay: The interval between IP checks.

retry_delay: Wait n seconds after a fail.

dns_nameservers: List of DNS resolvers used to resolve dns_record_ipv4 and dns_record_ipv6 at startup.

ipv6_prefix_length: The prefix length, delegated by the ISP. Generally this is 56, but can be 48 in some ISP.

ipv6_interface: The local interface on which the IP checks will be made.
The is generally an ethernet interface connected to the local network.

dns_record_ipv6: The DNS record that we will check the IP against.
If the current IP is different, this will trigger a DNS update.

The following are optional:

remote_ipv4_server_ip: IP address of the remote UDP server returning the client IPv4 address.
See https://github.com/Mathis-6/udp-my-ip

remote_ipv4_server_port: Port for remote_ipv4_server_ip.

bind_ipv4: The IPv4 address to bind to when sending packets to remote_ipv4_server_ip.

ipv6_prefix_cache_path: OPTIONAL: Writes the 16-bytes IPv6 prefix in this file.
Can be used by other applications to determine the local network.

ipv6_mask_cache_path: OPTIONAL: The 16-bytes mask obtained by ipv6_prefix_length will be written to this file.
Can be used by other applications.

dns_record_ipv4: Same thing as dns_record_ipv6, but optional.

shell_commands: List of commands to execute after the IPv6 prefix has changed.

ionos.zone_id: Your DNS zone ID.
ionos.api_key: The account API key.

cloudflare.zones: The list of zones to update in the form of
account api key: [list of Zone IDs to update]

The account API key can be obtained in your Cloudflare dashboard:
My Profile > API Tokens > Create token > Edit zone DNS (Use template)
In Zone Resources select include All zones then click Continue

To add a zone, click on a domain you added in your dashboard.
On the bottom right, you will see a Zone ID Copy the value and add it to the config.

If you don't use some settings, simply remove them from the config.json file.

Running the service

Create a service file as follow:

nano /etc/systemd/system/update-ddns.service

And paste this content

[Unit]
Description=Automatically update domains with dynamic IPv6/v4
After=multi-user.target

[Service]
Type=simple
Restart=no
ExecStart=/usr/bin/python3 -u /path/to/update-ddns.py --config /path/to/config.json

[Install]
WantedBy=multi-user.target

Update-ddns use the ip shell command to delete the old IP address after an IPv6 update.
If the service is not run as root, you will need to give the user a sudo access to the ip command without password.