dd2s

Simple Dynamic DNS client for updating hostnames on dyndns2 servers.

I needed a simpler solution than ddclient that would support dyndns2 servers. It also had to support updating multiple hostnames at once, since I am using a dyndns2 implementation on AWS Route 53, which cannot update multiple hostnames in one request.

Behavior

• Runs as a simple systemd service.
• Only supports updating hostnames over the dyndns2 protocol.
• Private IP hostnames not supported.
• Multiple hostnames can be updated using a single set of credentials.
• Multiple URLs can be selected for external IP checkers.
• When all IP checker URLs are down, it will keep retrying and log the errors.
• By default, waits 60 seconds before it starts over and checks the IP again.

Instructions

Prerequisite: Python 3.

Add a new user and fetch the project files:

$ sudo useradd -r -s /bin/false dd2s
$ cd ~
$ git clone https://github.com/wriches/dd2s.git

Copy the project files:

$ sudo cp dd2s/dd2s.service /etc/systemd/system/
$ sudo cp dd2s/dd2s.conf.example /etc/dd2s.conf
$ sudo mkdir /usr/local/lib/dd2s
$ $ sudo cp dd2s/dd2s /usr/local/lib/dd2s/

Change permissions:

$ sudo chmod 644 /etc/systemd/system/dd2s.service
$ sudo chown dd2s:dd2s /etc/dd2s.conf
$ sudo chmod 600 /etc/dd2s.conf
$ sudo chown -R dd2s:dd2s /usr/local/lib/dd2s
$ sudo chmod 700 /usr/local/lib/dd2s/dd2s

Edit configuration file:

$ sudo vim /etc/dd2s.conf

Optionally, if using SELinux:

$ sudo restorecon -rv /usr/local/lib/dd2s

Load the service, enable it, start it and check the status:

$ sudo systemctl daemon-reload
$ sudo systemctl start dd2s
$ sudo systemctl status dd2s

Example output:

May 24 03:03:25 [localhost] systemd: Started Simple Dynamic DNS client.
May 24 03:03:26 [localhost] dd2s: DEBUG - Updating IP for host my.example.com: good 123.45.67.89
May 24 03:03:26 [localhost] dd2s: DEBUG - Updating IP for host server.example.com: good 123.45.67.89
May 24 03:03:27 [localhost] dd2s: DEBUG - Updating IP for host host.example.com: good 123.45.67.89