DomiStyle/gandi-dyndns

Dynamic DNS for gandi.net

gandi_dyndns

Notes

This script uses the old XML-RPC API by Gandi. If you updated your DNS records to their new LiveDNS service you need to use this script instead.

Original script by Jason T. Bradshaw. This version was modified to receive an updated IP via an CLI argument rather than depending on external services. This makes it simpler to use for Dynamic DNS setups where the router/firewall already knows the external IP address. A common setup would be a pfSense firewall with a custom Dynamic DNS provider.

This implements a simple dynamic DNS updater for the Gandi registrar. It uses their XML-RPC API to update the zone file for a subdomain of a domain name to point at the external IPv4 address of the computer it has been run from.

It requires a server running a reasonably recent version of Python 2. It has been tested on Ubuntu/Arch Linux using Python 2.7.

Walkthrough

Last updated August 8th, 2016.

Say you'd like to be able to access your home server externally at dynamic.example.com.

API Key

First, you must apply for an API key with Gandi. Visit https://www.gandi.net/admin/api_key and apply for (at least) the production API key by following their directions. Once your request has been approved, you can return to this page to retrieve the production API key.

A Record Setup

Then, you'll need to create a DNS A record in the zone file for your example.com domain. This is how you'll access your server over the Internet at large!

1. Visit https://www.gandi.net/admin/domain and click on the example.com domain.
2. Click on "Edit the Zone" under "Zone files".
3. Click "Create a new version".
4. Click "Add".
5. Change the values to:

Field	Value
Type	A
TTL	5 minutes
Name	dynamic
Value	127.0.0.1

1. Click "Submit".
2. Click "Use this version".
3. Click "Submit".

Script Configuration

Then you'd need to configure the script.

1. Copy config-example.json to config.json, and put it in the same directory as the script.
2. Open it with a text editor, and change it to look like the following:

{
  "api_key": "yourtwentyfourcharapikey",
  "domains": { "example.com": ["dynamic"] }
}

You can apply for/retrieve your production API key at https://www.gandi.net/admin/api_key.

If you'd like to update more than one record with the external IP, simply add more values to the list in the domains dict:

  "domains": { "example.com": ["dynamic", "@", "mail", "xmpp"] }

If you'd like to update multiple domains, add more keys to the domains dict:

  "domains": {
    "example.com": ["dynamic"],
    "example.org": ["www"]
  }

1. Save and close the file.

Notes

The first time your A record is configured, it may take several hours for the changes to propogate through the DNS system!

We set the A record's TTL to 5 minutes so that when the address is dynamically updated by the script, that's the (hopefully) longest amount of time that would pass before the DNS system caught up with the change. Setting this much lower wouldn't be of much use, and could even cause DNS errors (see http://www.zytrax.com/books/dns/info/minimum-ttl.html).

Configuration

config.json

Config values for your Gandi account and domain/subdomain must be located in a config.json file in the same directory as the script. config-example.json contains an example configuration including all configurable options, and should be used as a template for your personal config.json.

Use

Pass an IP address to the script and it will update your records according to your config.json file.

./gandi_dyndns.py YOUR_IP_HERE

For usage with pfSense or any similar firewall/router with options for custom dynamic DNS providers you can use a simple PHP script like this:

<?php
   if(isset($_GET['ip']) && filter_var($_GET['ip'], FILTER_VALIDATE_IP))
   {
      $output = shell_exec('./gandi_dyndns.py ' . $_GET['ip']);
      echo "OK";
   }
   else
      echo "FAIL";
?>

Call it from your pfSense under "Services -> Dynamic DNS":

Field	Value
Service Type	Custom
Interface to monitor	WAN
Interface to send update from	LAN (also works with WAN)
Update URL	http://dyndns.example.org?ip=%IP%
Result Match	OK

NOTE: dyndns.example.org points to the web server where the above PHP script and the Python script are hosted. While you can host this directly on your firewall I wouldn't recommend it.

IMPORTANT: Make sure to restrict the server where you are hosting your dynamic DNS script to only allow access from the IP of your firewall. If you can't do this because your web server is located on the WAN side you can add another HTTP parameter for a password authentication.