DNS record for newbies

#cloud #webdev #programming #beginners

DNS (Domain Name System) is the protocol that clients use to find the IP address of a server.

*I will explain the DNS role in below steps

User
  ↓
Web Browser
  ↓
Enter domain in search bar (e.g., example.com)
  ↓
Check local DNS cache
  ├─ If IP found → go to server
  └─ If not found → ask DNS resolver
          ↓
      DNS Resolver (ISP)
          ↓
      Check root DNS servers
          ↓
      Check TLD DNS servers (.com, .net, etc.)
          ↓
      Check Authoritative DNS server (NS record)
          ↓
      Get A / AAAA record (IP address)
          ↓
Return IP address to browser
  ↓
Browser connects to web server using IP
  ↓
Server sends back website data
  ↓
Browser renders website for user

DNS Records

There are something called DNS Records which tie the complete picture of how internet finds something.

NS record : points to DNS server responsible
A/AAAA record : Tells the IP address of the server
CNAME record : It maps one domain name to another domain name instead of pointing directly to an IP address
MX record : directs mails to the correct mail server
TXT record : mainly used as external verification info

DNS Record Comparisons

CNAME vs A/AAAA

A / AAAA Record: Points a domain directly to an IP address.
CNAME Record: Points a domain to another domain name, which then resolves to an IP via an A/AAAA record.
Use CNAME: When multiple subdomains share the same IP as the main domain (centralized management).
Use A/AAAA: When the domain/subdomain has its own unique IP or for root/apex domains.

NS vs MX

NS (Name Server) Record: Points to the DNS servers responsible for a domain. Controls all DNS records for that domain.
MX (Mail Exchange) Record: Points to the server that handles emails for the domain.
Key difference: NS = controls DNS, MX = handles emails.