The Domain Name System (DNS) is a system that translates domain names into IP addresses. It's like an internet phone book, allowing people to access websites using words instead of numbers.
Why is DNS important?
Makes the internet more accessible: DNS lets users easily visit websites without needing to remember complex IP addresses.
Facilitates communication: DNS enables hosts on a local network to communicate with each other.
Protects against malware and phishing: DNS can block harmful websites and filter out certain categories of sites.
How does DNS work?
A user types a domain name into their browser.
The DNS server finds the IP address that matches the domain name.
The browser uses the IP address to send data to the website's content delivery network (CDN) edge servers or origin servers.
The user can then access the website's information.
What are DNS record types?
DNS record types are records that provide important information about a hostname or domain. These records include the current IP address for a domain.
The most common types of DNS record
A record - The record that holds the IP address of a domain.
AAAA record - The record that contains the IPv6 address for a domain (as opposed to A records, which list the IPv4 address).
CNAME record - Forwards one domain or subdomain to another domain, does NOT provide an IP address. .
MX record - Directs mail to an email server. .
TXT record - Lets an admin store text notes in the record. These records are often used for email security. .
NS record - Stores the name server for a DNS entry.
DNS Hierarchy
The Domain Name System (DNS) hierarchy is like a tree, starting at the root level and branching into domains, subdomains, and records. The root level includes the root zone, which is managed by root name servers. Below the root level are authoritative name servers, which manage the records for their associated domains.
Root level
The root level is the top of the DNS hierarchy
The root zone is managed by root name servers
Root name servers redirect requests to the appropriate top-level domain (TLD) name servers
Top-level domains
TLDs are the next level below the root level
Examples of TLDs include .com, .net, .org, and .edu
TLD servers manage the subdomains and records for their TLD
Authoritative name servers
Authoritative name servers are the final stop for DNS queries
They respond to DNS queries from clients
Authoritative name servers contain DNS resource records with information about a domain
