DynDNS Update
![[example outputs]](./it/bash_scripting/dyndns_update/dyndns_update.png "example outputs")
Description
This script allows one to update a specified subdomain registered at INWX.de with a new IP address. While this IP will most probably be the publicly available IP of your router, it is possible to set the domain record to any valid public IP address.Since this effectively allows you to create your own dynamic DNS service, you no longer depend on the limitations of free dynamic DNS services.
Usage
In order to easily run the script from the command line, I defined the following shell alias:alias dyndns_update='~/bin/dyndns/update_domain.sh'
The picture on the right shows the two possible use cases:
-
Case 1:
one's current public IP is different from the one registered in the subdomain's DNS record
Besides the old IP and its time of registration one's current public router IP and the current IP of the subdomain are displayed. -
Case 2:
one's current public IP is equal to the registered one
In this case the time of registration and the set TTL are shown. Besides this, also the current public router IP and the current IP of the subdomain are displayed.
Note: The TTL is the minimum amount of time that has to pass before the next update can be performed. Together the time of the last update and the TTL tell one, how much time remains until the next update is possible. While the script contains code to automatically calculate and display the remaining time, I prefer to see the TTL.
At the moment 3600 seconds is the smallest possible TTL value INWX allows.
Download
- dyndns_update.sh v1.0 sh