Linode is a popular VPS hosting provider. NearlyFreeSpeech is a popular bare-bones Web hosting provider. Both provide DNS hosting with an API. These shell scripts allow you to update a DNS record remotely—from, say, a home server running on a dynamic IP address.
You will need:
Download the shell script at Github.
NearlyFreeSpeech provides a Perl library that can access the DNS API, but does not distribute the source code. Therefore, this script is in two parts: a shell script that can be run remotely and a helper Perl script that must reside on a NearlyFreeSpeech server. The shell script assumes that the helper Perl script is protected with HTTP Basic authentication.
You will also need a NearlyFreeSpeech API key.
Download the shell script and helper Perl script at Github.
This is free software. It is released to the public domain without warranty.