Some basic concepts - Web Sites, Domain Names, Email
There are generally 4 things associated with a website.
- The domain name registration
- The domain name maintenance
- The web server hosting
- Possible email hosting
In many cases 2-4 are done by the same organization but that is not always the case.
A domain name must be registered with one of the few dozen official registrars. Besides these official registrars, there are hundreds of companies that serve as the distribution channel (or resellers) of domain registration services. You pay the registrar (or the reseller) a fee per year to maintain ownership of the domain. That registration includes specifying who does the DNS management for that domain name (this is done by specifying the name of the DNS servers of the maintainer). (More detail on domain registration and name servers)
The DNS maintenance is done by anybody that has a DNS server. The DNS maintainer (also called the DNS hoster) sets up the tables needed to direct requests for various systems in the domain to the correct IP address. For the minimum scenario above, this would include definitions for the web server (typically named www) and the mail server for the domain.
The web site is hosted on a web server. The IP address of the web site must be setup by the DNS maintainer so requests get to the right site.
The email hoster is anyone who maintains an email server. The IP address of the email server must be setup by the DNS maintainer to point to the correct mail server. The mail server must be set up to recognize the individual mailboxes in that domain and to process them correctly.