DNS servers

A Domain Name System (DNS) server "resolves," or translates, domain names (such as "example.com") into machine-readable Internet Protocol (IP) addresses. An IP address is the base foundation by which all computers on the internet are known. The IP address is that discrete set of numbers with all those periods, ie. 192.168.1.1 that discretely identify a computer on the world wide web or other network. Domain names are easier for humans to read and remember but are not necessary to connect to a website. One may type "http://1.23.45.117" instead of "http://example.com" and arrive at the same site.

Each domain name has a DNS server maintained by the domain's administrator – for instance, the United States keeps track of ".us" domains. The entire DNS system is a "distributed database," that is, it operates as a single database even though it is distributed across a staggering number of machines and administrators. When a DNS server receives a request for an IP address (for example, from a web browser), it responds either by providing it (if it already has the IP address) or by sending the request to another DNS server. This process continues until the IP address is found. If the domain name does not exist, the DNS server returns an error message.