DNS

The domain name system, or DNS, is the Internet equivalent of a phone book. It maintains and translates domain names into Internet Protocol (IP) Addresses. DNS works on three levels.

Level 1: Registration

The first level of DNS is the registrar. The right to the use of a domain is given by registrars, who are accredited by the Internet Corporation for Assigned Names and Numbers (ICANN). This level is where domain ownership and the contact details are managed.  The nameservers (Level 2) are also set at this level.  The WHOIS protocol is a database that allows for the use of nameservers, the next level of the DNS.

Level 2: Nameservers

Nameservers are the most fundamental part of the DNS. Nameservers allow for domain names to be used instead of IP Addresses. IP addresses are stored in the Address Records or A Records for short. Nameservers take the current domain name and convert from the domain to an IP found in an A record. 

However, there are cases where a user may want multiple aliases for one domain name. In this instance, a CNAME (Canonical Name Record) would be used.  A CNAME takes one name (Ex: www.google.com) and return its canonical name (Ex: google.com) this alias name is then translated to an IP using an existing A record.

There are also Mail Exchange, or MX, Records that function when the lookup is trying to determine where to send an email message.  The MX record converts to a name and this name is then translated to an IP using an existing A record.

Level 3: Hosting

This brings us to the final level of DNS. The final level of DNS is split into two different sections: web hosting and email hosting.  Web hosting is the hosting for the domain, which may have its own IP Address completely different from the email hosting. For instance, having GoDaddy for web hosting but Google for email hosting. They may also be off of the same hosting account, such as a GoDaddy email hosting with a GoDaddy web hosting.