+ What is DNS?
DNS (Domain Name System) is a network service that translates human-readable domain names (like google.com) into IP addresses that computers use to communicate.
+ Why is DNS important in computer networks?
- Humans remember names, not IP addresses
- Enables Internet browsing
- Critical for applications, email, and services
- Used in LAN, WAN, and enterprise networks
+ How does DNS work? (Name Resolution Process)
- User enters a website name
- Client checks local DNS cache
- Query sent to DNS server
- DNS server returns IP address
- Browser connects using IP
+ Common DNS Record Types
- A – Maps domain to IPv4 address
- AAAA – Maps domain to IPv6 address
- CNAME – Alias for another domain
- MX – Mail server record
+ Local DNS vs Public DNS
Local DNS is used inside organizations, while public DNS (Google DNS, Cloudflare DNS) is used for Internet name resolution.
+ Real-World Example
In enterprise networks and hospitals, internal DNS resolves server names, applications, and services without exposing them to the public Internet.