DNS Servers

DNS servers receive requests or queries and respond by resolving that query and returning the information mapped to it, if it exists. There is not one canonical DNS server for the entire Internet. Instead, when a domain is registered, that registration is listed on a series of ICANN-run servers scattered around the world. Contained in that registration is information about where the authoritative DNS information is stored for that domain. This is usually, but not necessarily, a DNS server or set of DNS servers operated by the domain name registrar.

DNS requests work in a hierarchical fashion. Here is an example:

Image A full request comes ...

Get Ubuntu Unleashed 2014 Edition: Covering 13.10 and 14.04,Ninth Edition now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.