Does setting an A record for a root domain set it (automatically) for subdomains?

Question

I bought a domain from Dreamhost, but my servers are actually running on Amazon's AWS. I have an Elastic IP, say 1.1.1.1.

In the Dreamhost panel, I've added an A record for my domain name, pointing it to 1.1.1.1.

My question is, are all subdomains (e.g. www.mydomain.com, a.mydomain.com, etc.) automatically mapped to 1.1.1.1 as well, because the root is? Or do I have to add separate rules for each subdomain?

Answer 1

If you want everything for mydomain.com to point to 1.1.1.1 you will need to setup a wildcard dns entry in your Dreamhost panel. Have a look at this blog which give some advice on how to do just that.