DNS Resolver

What is DNS Resolver?
It is a system that converts a domain name into an IP address
also acts as a middleman between client and DNS servers

Main Components involved
Client which requests the domain
Recursive resolver which handles the query
Root server which directs to TLD
TLD server which points to authoritative server
Authoritative server which gives final IP address

Approach
Step 1
User enters a domain name in browser
Step 2
System checks local cache if IP already exists
Step 3
If not found request goes to DNS resolver
Step 4
Resolver checks its cache
Step 5
If not found resolver contacts root server
Step 6
Root server redirects to TLD server
Step 7
TLD server redirects to authoritative server
Step 8
Authoritative server returns the IP address
Step 9
Resolver sends IP back to client
Step 10
Client connects to the actual server

Why this works???
Because DNS follows a hierarchical structure
Each server has specific responsibility
Resolver collects information step by step until IP is found

Caching makes it faster by avoiding repeated full lookups

Constraints
Initial lookup can be slow if not cached
Multiple servers are involved so delay can happen
If DNS server fails resolution will fail