DNS Flashcards
(5 cards)
What is DNS?
DNS maps domain names to their corresponding IP addresses. This mapping is essential because computers communicate using IP addresses, while humans prefer to use easy to remember domain names.
Let’s explore what exactly happens in the DNS resolution process, first is the client query, when a user attempts to access a website or online service, their client.
In this case a web browser, initiates the DNS resolution process by sending a query to a recursive name server, usually provided by their Internet service provider or configured on their local network.
What is the function of recursive name server?
The recursive name server sends a query to the TLD name server, this query asks for the IP address of the authoritative name server for the requested domain.
The recursive name server caches the IP address and returns it to the client, allowing the client to establish a connection with the desired server.
This resolution process happens quickly, often within milliseconds, thanks to caching mechanisms and the distributed nature of the DNS infrastructure.
What are resource records?
DNS stores information in the form of resource records or or RR,S which are data entries that map domain names to various types of information.
The most common types of resource records include A records which map a domain name to an IPV four address, the A stands for address AAAA records map a domain name to an IPV six address.
The four A’s represent the fourfold increase in address space from IPV four, CNAME or canonical name records alias one domain name to another domain name. When you set up a CNAME record, you are directing traffic that goes from one domain to another domain.
What are additional DNS records?
MX records specify the mail servers responsible for handling email for a domain, NS records specify the authoritative nameservers for a domain. And TXT records store arbitrary text based data often used for various purposes like email security and domain ownership verification.
These records are stored and managed by authoritative name servers, enabling the translation of domain names into various types of information required for different Internet services.
What are DNS zones?
DNS zones ensure a distributed and scalable system for managing and resolving domain names across the Internet, enabling seamless communication between servers and clients.
A zone contains a collection of resource records that define the mappings between domain names and various types of information, such as IP addresses, mail servers, and name servers.
Each one has authoritative name servers responsible for storing and serving the resource records within that zone, lastly, DNS is a critical component of the Internet’s infrastructure.
