frosas.net

Last week my ISP changed my home connection to a dynamic IP configuration. The fact is that I somehow needed to access to this connection so I've thought a dynamic DNS would solve the problem.

The solution was as simple as creating a free account in any of the dynamic DNS providers (I've chosen DynDNS), create a new hostname and configure my router to update it as needed.

The problem is that I had to use one of the DynDNS domains but I wanted to use my own one as it would be easier to remember. Luckily recently I did some CNAME configurations at work and I've thought this would be a perfect scenario to use it.

The idea is simple:

1. In the dynamic DNS provider, create the dynamic hostname (eg, foo-example-com.dyndns.org)

2. In your domain nameserver, create a CNAME entry pointing from the final hostname (eg, foo.example.com) to the dynamic one.

3. To ensure it is working correctly you can check how the final hostname is resolved:

   $ dig foo.example.com
   
   (...)
   
   ;; ANSWER SECTION:
   foo.example.com.                79307   IN      CNAME   foo-example-com.dyndns.org.
   foo-example-com.dyndns.org.     60      IN      A       1.2.3.4
   
   (...)