DynR53

From Notes

dynR53 is a simple bash script which checks/updates the detected public facing IP address of you system as it relates to a predefined AWS Route 53 hosted zone DNS entry. Basically, it's dynamic DNS for AWS Route 53!

Contents 1 Disclaimer 2 Download 3 Prerequisites 4 Getting Started

Disclaimer

The script is written for Red Hat style Linux distributions (but should work fine on most any *nix flavor), is open source, free to use and free to modify. I am, by no means, a professional developer- the script may contain bugs and inefficiencies (just fair warning). Constructive feedback is greatly appreciated; code contributions would be awesome.

Download

Grab a copy of the script here: http://cdn.improvisedscience.org/cdn/projects/dynR53/dynR53.tgz

Prerequisites

1. perl-XML-Xpath
2. perl-Digest-HMAC
3. dnscurl.pl for AWS Route 53 and its prerequisites http://aws.amazon.com/code/Amazon-Route-53/9706686376855511
4. An AWS account along with your AWS id and key (see my AWS credentials article)
5. A public domain name already hosted by Route 53 (see my Route 53 article to get started)

Getting Started

After untar'ing the package, check out the README file; you'll need to make a few basic modifications to fit your environment:

1. Ensure the above listed prereq's are in place.
2. If you don't already have an aws-secrest file in place, modify the one provided by the tarball by adding your AWS id and key.
3. Edit dynR53.bash; some initial variables need to be set:

• • DNSCurl: set to the full path of the dnscurl.pl script
  • myHostName: the host name you wish to check/update (ie: "home")
  • myDomainName: the domain hosted by Route 53 in which your host RR will reside (ie: "example.com"; therefore, the RR home.example.com would become your dynamic RR)

1. Next, you may wish to modify a few other variables:

• • myTTL: the time to live for the RR, in seconds.
  • route53API: you shouldn't need to change this unless/until the Route 53 is updated by AWS; but then this entire script may become broken. If you change this var, also change the next one...
  • route53APIDoc: you shouldn't need to change this unless/until the Route 53 is updated by AWS; but then this entire script may become broken. If you change this var, also change the previous...

That's it! Run the script. If all goes well, set up a cronjob:

15 * * * * /usr/local/dynR53/dynR53.bash > /dev/null

This job will check/update your public IP and dynamic RR every 15 minutes.