If you are running your own DNS, you have registered a domain, eg.:

domain.com

...and then registered the name server addresses so your hosted customers can use for their domains. Let's say you have these name servers that are registered:

ns1.domain.com
ns2.domain.com

But here's the question - Do you need to keep that domain (domain.com) registered? In other words, if the domain expires, will the name server addresses that are based on that domain, also go out of business?

Thanks much!

YES! If the domain expires, ALL of your records based on that domain will disappear, as well. This means that not just ns1 and ns2, but all *.domain.com subdomains will go away.

--Alden

Simple Answer: Yes, your domains will go down.

Complex Answer: Your name servers will still serve the records up if queried directly, but no one will know to do that unless you specifically gave them directions. For the average user looking for your site, this will not be feasible. Many people will do this for QA purposes when deploying new infrastructure.

As everyone else said, yes you want to keep it registered.
You can register a .com or .net domain within Orbit for $6.99 a year so that cost should just be part of your DNS operations; and a low cost at that.

Or if you are registering a good number of domains, signup for one of the planet's http://www.resellone.net reseller accounts for reseller pricing (but you have to maintain a deposit in your account in exchange for the better pricing), domain registration API access, bulk change ability, and the ability to create client sub-accounts for domain management.