website shutdown after alteration of naming server

Before I say anything else, please note that this is not a formal technical support channel. The majority of the answers here are posted by community members who are not on DynDNS' staff. If you need to get in touch with DynDNS' sales or support teams, contact them at sales (at) http://dyndns.com or support (at) http://dyndns.com, respectively.

I take it that you are a consultant hired by a third party. If they want the DNS for the domain hosted by DynDNS, they need the Custom DNS service. I recommend following the steps below to ensure a seamless transition.

1. Purchase Custom DNS for the domain. It would probably be better to create a separate account for your customer (if they don't already have one), rather than using your own account. That way, they will have control over the billing and the DNS zone themselves.
2. Make sure the zone is preloaded on DynDNS' servers before delegation:

   You can force activate your Custom DNS zone once you purchase it and setup your DNS records. To do this, go into your Custom DNS preferences. Once that is done, give it a couple hours to preload the zone on our servers.

3. Set up the DNS records as desired. Make sure you re-create the records for the website as currently defined in the old DNS zone.
4. Delegate the DNS to DynDNS' name servers, as outlined in the Custom DNS How-To. Please be prepared that this change can take 12-48 hours (or even more) to propagate, depending on the registrar and registry in question.
5. If you have created any dynamic hosts within the domain, do make sure you configure and enable an update client to update the hostnames when the IP address changes.

Good luck.

In case you want to DNS-host your existing registered domain (or just a subdomain) at DynDNS, you had to purchase Custom DNS. The website would still be reachable, of course. This is the purpose of DNS hosting. In case you also want to run a mail server at a dynamic IP address, you would probably also need the one or other of the mail services.