I have always wondered this. You park your domain at a webhost and add webhost's nameserver to registrar. After that, the domain points to your website at webhost server.
Why don't I need to add an A record that points to webhost IP or add an A record for www subdomain that points to webhost IP? I just add nameserver and it works.
I thought that to point to webhost I would always need to create an A record with webhost IP and add webhost nameserver at DNS management website. How do they work?
Thanks for your reply. What I want to do is using my subdomain name at other webhost. For example using blog.myname.com at other webhost lets say hostgator.com while myname.com is hosted at dreamhost vps. As you know I could do this by adding A record in my bind DNS zone at my vps. I want to add only hostgator nameserver to my DNS zone to propagate my subdomain to hostgator.