What is DNS?

DNS (Domain Name System) translates human-readable domain names (e.g., www.example.com) into machine-readable IP addresses (e.g., 192.168.1.1), enabling users to access websites using names instead of numbers.

How does DNS work?

• Your device queries a DNS resolver.
• The resolver checks its cache or queries root servers → TLD servers → authoritative servers.
• The authoritative server provides the IP address, which is sent back to your device.

Common DNS Records

• A: Maps a domain to an IPv4 address.
• AAAA: Maps a domain to an IPv6 address.
• CNAME: Aliases one domain to another.
• MX: Specifies mail servers for email.
• TXT: Stores text (e.g., for verification or SPF).
• NS: Identifies authoritative DNS servers.

Key DNS Concepts

• Resolver: Intermediary server that queries DNS on your behalf.
• TLD: The last part of a domain (e.g., .com, .org).
• Authoritative Server: Holds the official DNS records for a domain.
• Caching: Temporarily stores DNS results to speed up future queries.
• DNSSEC: Adds cryptographic security to DNS to prevent attacks.

Common DNS Issues

• Propagation Delay: Time for DNS changes to update globally (up to 48 hours).
• DNS Leak: DNS queries exposed to your ISP, even when using a VPN.
• Hijacking: Malicious redirection of DNS queries to fake servers.

Why is DNS Important?

DNS is essential for the internet to function, allowing users to access websites and services using easy-to-remember names instead of numerical IP addresses.