DNS: Domain Name Resolution Basics
- Networking Fundamentals & OSI Model
- TCP/IP Model
- Network Topologies
- IP Addressing & Subnetting
- Routing Algorithms & Protocols
- Switching Concepts
- Transport Layer Protocols (TCP & UDP)
- Application Layer Protocols
- Network Security & Firewalls
- Wireless Networking & Wi-Fi
- Network Address Translation (NAT)
- DNS Deep Dive
- Congestion Control & Flow Control
- Error Detection & Correction
- Network Devices
- VPN & Tunneling
- Load Balancing & CDN Networking
- Socket Programming
- Network Troubleshooting Tools
- Physical Layer & Transmission Media
- Data Link Layer & MAC Addressing
- Ethernet Protocol
- ARP (Address Resolution Protocol)
- ICMP Protocol
- Unicast, Multicast, Broadcast and Anycast
- Proxy Servers
- Port Numbers Reference
- Network Performance Metrics
- Quality of Service (QoS)
- Software-Defined Networking (SDN)
- HTTP/2 and HTTP/3 Overview
- 5G and Mobile Networks
- IoT Networking Basics
- VoIP Networking Basics
The Problem DNS Solves
Computers route traffic using IP addresses, but people don't want to memorize a string of numbers to visit a website. DNS (Domain Name System) exists to translate human-friendly domain names into the IP addresses computers actually need.
example.com --- DNS lookup ---> 93.184.216.34A Simplified Lookup, Step by Step
- Your device asks a DNS resolver (often run by your ISP): "What's the IP address for example.com?"
- The resolver checks its own cache first - if it recently looked this up, it returns the cached answer immediately.
- If not cached, the resolver queries the wider DNS system (covered in detail in a dedicated note in this section) to find the authoritative answer.
- The IP address is returned to your device, which then connects directly to that address.
A Useful Analogy
DNS functions like a phonebook: you look up a name, and it returns the actual number you need to actually make the connection. Just like phonebooks, this lookup system is distributed and hierarchical rather than one single giant list - no single server holds every domain name on earth.
Why Caching Makes DNS Fast
Because domain names rarely change their IP address, resolvers cache answers for a period of time (controlled by a TTL value, covered in its own note), so repeated lookups for popular sites are nearly instant rather than requiring a fresh full lookup every single time.
What the Internet Would Feel Like Without DNS
Every website would need to be remembered and typed as a raw IP address - workable for a handful of sites, but completely impractical for the millions of domains people visit. DNS is what makes the internet's naming system usable by actual humans.