How DNS works

This diagram shows what takes place when a visitor first types a web address into their browser:

1. The browser contacts a local name server (usually at their ISP) to ask for an IP address for a domain name.  If the local name server does not know the answer it will contact the root domain name server maintained by InterNIC.
2.  The root domain name server will return the IP address of the primary name server responsible for the domain being requested.
3. The primary name server becomes the next machine contacted by the local name server.
4. The primary name server holds the IP address for the domain name and satisfies the the local name server's request. Then the local name server can finally return to the web browser with the IP address.
5. (A secondary name server can be used as backup)
6. Using the IP address, the web browser can then contact the company's web server to request the web pages.

The process of transfering a domain name involves changing the records held by Internic (and also the records held on the primary and secondary name servers).  The part of the process that can take some time is ensuring that changes are only made by people who have the authority to administer the domain name in question.