The DNS tab works with name server(s) maintained by ISPConfig. If you run a single server ISPConfig setup, you can also run name server on that same host, just install bind following the Perfect Server Guide. If you have multiserver setup, you can create name server hosts to the multiserver setup. If you are resourcefull, you can set up name service zone transfers or otherwise copy the name service information to name servers outside ISPConfig setup, but this involves non trivial work to set it up. So basically, the answer to your question is yes, if you buy your name service from your hosting provider or some entity providing name service, you can not use ISPConfig DNS tab to maintain that name service.
Hey, thanks for your answer. So my domain is on GoDaddy, and my NS on cloudflare, so i think its useless for me? THX
It does not matter where you have registered your domain, all registrars allow you to specify which name servers are authoritative for your domain, that is provide the name service info for your domain. I know nothing of cloudflare, but unless you can setup those cloudflare name servers to do zone transfers from the name server you set up with ISPConfig, you can not use ISPConfig to set up your name server. Is the cloudflare offering somehow not to your liking? If you have only a few domains, it probably is not a big job to enter and maintain the name service information there. You can look at the DNS tutorial linked to in my signature to see how DNS is set up with ISPConfig.
