DynHost Updater

What is it?

This program is a dynamic DNS client for OVH's DynHost (https://docs.ovh.com/ie/en/domains/hosting_dynhost/). It will periodically check for a new IP address and update your (sub)domains when needed.

It uses scripts located in the scripts folder to retrieve IP addresses and handle error notifications, that way you can fully adapt it to fit your needs.

Installation

There are two scripts (install.sh and uninstall.sh) which will install DynHost as a Systemd service on Linux. It requires Python 3.6+ and the packages inside requirements.txt to work.

The scripts in the scripts folder in this repository require curl to be installed.

# Dependencies for Debian / Raspbian / Ubuntu
sudo apt update
sudo apt install python3 python3-pip git

# Dependencies for Arch / Manjaro
sudo pacman -Syu --needed python python-pip git

# Clone the repository
git clone https://github.com/hoot-w00t/dynhost-updater.git
cd dynhost-updater

# Install
sudo ./install.sh

# Or uninstall
sudo ./uninstall.sh

To manage the service you can use sudo systemctl start/stop/status dynhost.service. By default log files will be in /var/log/dynhost/.

Configuration

You can take a look at the examples and the scripts folders to see basic configurations. You can use them as templates.

The program will check its configuration file for any errors before running, you can force a syntax check without starting the program with the --syntax parameter. If you need to disable this syntax check, for instance if it malfunctions, use the --no-syntax-check parameter.

Settings

The settings tell how the program should work.

• update_delay is the delay between each check for changed IP addresses (in seconds)
• fallback_ip_method is the default IP address script to use if the main one fails. (Can be enabled/disabled for each host individually)

The on_error block tells the program what to do in case of an error updating a DynHost:

• enabled is either true or false and enables/disables executing a script in case of an error
• script is the script name that should be executed when an error occurs

The program will provide the host's name as a parameter to the script.

"update_delay": 300,
"fallback_ip_method": "ipify",

"on_error": {
    "enabled": false,
    "script": "print"
}

Authentication

You can configure multiple credentials to authenticate multiple DynHosts, where:

• auth1 is the name of the credentials
• username is the DynHost username you created (your_domain.com-suffix)
• password is the associated password

"auth1": {
    "username": "domain.com-suffix",
    "password": "password"
}

Hosts

You can configure as many hosts as you need, where:

• root is the name of this host
• hostname is the full domain/sub-domain to update
• auth is the authentication name to use
• last_ip is used by the program to know when it needs to update the DynHost (you can set it to the current IP address it has)
• ip_method is the script name to gather the current IP address that this host should have
• fallback is either true or false and enables or disables the use of the fallback IP script if the one you specified doesn't return a valid IP address.

"root": {
    "hostname": "mydomain.com",
    "auth": "default",
    "last_ip": "127.0.0.1",
    "ip_method": "ipify",
    "fallback": true
}

Scripts

Scripts just need to be executable, using chmod +x your_script_file.sh on Linux.

You can place your scripts inside the existing scripts folder before installing with the install.sh script. All files inside the folder will be installed and rendered executable.

Note: The program expects raw IP addresses such as 127.0.0.1, you need to take care of the parsing inside the script. Any whitespaces will be ignored.

Example for Linux

#!/bin/sh

curl -s something.com/what_is_my_ip
any_other_command

Examples for Windows

@echo off

curl -s something.com/what_is_my_ip

@curl -s something.com/what_is_my_ip

Logging and arguments

If you need to adjust settings such as logging which are given as arguments to the program you will need to edit the dynhost.service file before installing or if you already installed /etc/systemd/system/dynhost.service.

If you modify the installed service file you will need to execute systemctl daemon-reload and then you can restart the service to apply the changes immediately.

Note about IPv6

At the time I am writing this, OVH's DynHost only supports IPv4, the program accepts IPv6 addresses returned from scripts but DynHost does not create/update an AAAA field.