At the most basic level, Domain Name System, or DNS as it is commonly known, is an Internet service that
translates domain names into IP addresses and is an essential component of any network. There are two
types of DNS servers: authoritative and non-authoritative.
Authoritative DNS •
The response headers returned from the
origin web server. If the headers indicate that content
should not be cached then it won’t be.
• Non-Authoritative DNS
Also referred to as a Local DNS (LDNS) or a caching DNS server -- is often located near the DNS
client, caching DNS answers received from Authoritative DNS servers, speeding future resolution
requests. Local DNS servers are usually provided by ISPs or an enterprise’s IT department