A Domain Name System Tutorial
Here is a collection of my study notes on the Domain Name System protocol. DNS Hierarchy and Database Remember the format of a URL: Figure: URL format – copyright www.examsmyantra.com The Domain Name System protocol is hierarchical. It’s not flat. If you’ve worked with UNIX and Linux file systems, you’ll notice there is a similarity. The next thing you’ll notice is you have a “dot” symbol at the top of the pyramid. This is the root domain, or root name server . Immediately below it, there are extensions that we all know such as “com” and “org”. These are the Top Level Domains TLD s: The DNS hierarchy © Stanford University Below the TLDs are the second-level domains , such as Cisco, Microsoft, etc. And every domain below them is simply called sub-domain : Figure: DNS Structure – © usahitman.com The domain name is segmented into different domain levels. Each domain level contains many servers. For example, ...