Gandi Dynamic DNS
Cron job to auto update DNS records when WAN IP changes using Gandi Live DNS API on Debian GNU/Linux
(This is obviously for a domain hosted by Gandi.net)
- Debian GNU/Linux 10 (Buster)
- curl :
apt-get install curl
- dig :
apt-get install dnsutils
Fetch script from git repo, install and configure
git clone https://gitlab.com/lab.8916100448256/gandi-dynamic-dns.git ./gandi-dynamic-dns cd ./gandi-dynamic-dns sudo bash ./install.sh
Then configure DNS record info and API key in file /etc/live-dns/live-dns.conf
How it works
Cron job definition to check for WAN IP change and call Live DNS API to update the DNS record if necessary.
By default runs the check/update script 2 times per hour, at every hour past 12 and 42 minutes.
Configuration file for the check/update script.
Needs to contains 3 environment variable definitions
- DOMAIN="domain.tld" : Replace domain.tld with your domain name
- RECORD="host" : Replace host with the sub domain you want to update when WAN IP changes
- APIKEY="Your-API-Key" : Replace with you API key generated in security section of your profile on Gandi web interface.
Check this page if you don't know the APIKey of your Gandi account : https://docs.gandi.net/en/domain_names/advanced_users/api.html
This is the script that is called by the cron job.
- First the WAN (external) IPV4 and IPV6 adresses are determined using http://me.gandi.net through curl
- Then they are compared to the A and AAAA DNS records retrieved through dig for the configured host and domain.
- In case of mismatch Gandi live DNS API is called to update the DNS records through curl using the configured APIKey
Information logs are written to the system log
For Example :
December 12 12:42:02 passerelle root: WAN IPv4 : 188.8.131.52 December 12 12:42:02 passerelle root: WAN IPv6 : 1111:2222:3333:4444:5555:6666:7777:8888 December 12 12:42:02 passerelle root: DNS IPv4 : 184.108.40.206 December 12 12:42:02 passerelle root: DNS IPv6 : 1111:2222:3333:4444:5555:6666:7777:8888 December 12 12:42:02 passerelle root: No need to update IPv4 DNS record for sub.domain.tld December 12 12:42:02 passerelle root: No need to update IPv6 DNS record for sub.domain.tld
This script is based on the mywanip.sh sample provided by Gandi on their GitHub