How DNS Works – Step by Step

Learn how DNS resolution operates step by step, from local caching to authoritative responses, and how Medianova DNS optimizes each stage for speed and reliability.

DNS resolution transforms a human-readable domain name into actionable network information — typically an IP address. Understanding how each stage of this process works helps Medianova users design fault-tolerant systems, debug DNS-related errors, and ensure reliable content delivery. Within Medianova’s DNS and CDN infrastructure, this resolution flow is optimized through Anycast routing, caching policies, a for consistent global performance.

Resolution Lifecycle Example

Let’s examine how a request for www.example.com is resolved, step by step.

1

Check Local DNS Cache

The client (browser or operating system) first checks its local DNS cache for a recent record. If a valid cached entry exists within its TTL, no external query is needed — resolution completes instantly.

2

Send Query to Recursive Resolver

If no local record is found, the client forwards the query to a recursive resolver (e.g., an ISP resolver or a public DNS service such as 8.8.8.8 or 1.1.1.1). The recursive resolver becomes responsible for retrieving the final authoritative answer.

3

Query the Root Server

The resolver starts at the root zone, asking which nameservers are responsible for the requested Top-Level Domain (TLD). Example query:

Q: What are the authoritative nameservers for .com?

The root server responds with a referral to the corresponding TLD nameservers.

4

Query the TLD Nameserver

The resolver queries one of the TLD nameservers to locate the authoritative nameservers for the target domain (example.com).

Q: What are the authoritative nameservers for example.com?

The TLD server responds with a referral to the domain’s authoritative nameservers.

5

Query the Authoritative Nameserver

The resolver sends a query to the authoritative nameserver for example.com, asking for the final record (e.g., A, AAAA, or CNAME) for www.example.com.

Q: What is the A record for www.example.com?
A = 93.184.216.34

This is the authoritative answer.

6

Return and Cache the Response

The recursive resolver returns the final IP address to the client. Both the resolver and the client cache the response for the TTL duration, improving performance for future requests.

DNS Resolution in the Medianova Platform

In Medianova’s architecture, DNS resolution is tightly integrated with CDN and Redirect systems.

• Anycast DNS routes each query to the nearest available authoritative node for optimal response time.

• CNAME records map your branded domain (e.g., cdn.yourdomain.com) to the assigned Medianova CDN hostname (e.g., yourzonename.mncdn.com).

• Redirect zones leverage DNS resolution to manage domain-level forwarding.

• Low TTL configuration minimizes propagation delays during record updates.

For details on DNS configuration, see Medianova DNS Service and CNAME & SSL.

Summary Table

Stage	Description	Optimization in Medianova DNS
Local cache	Client-side lookup before network query	Reduces repeated requests
Recursive resolver	Retrieves authoritative data	Anycast routing for low latency
Root & TLD queries	Navigate domain hierarchy	Global redundancy and caching
Authoritative nameserver	Provides final answer	Zone-based management for CDN & Redirect
Response caching	TTL-based storage	Configurable TTL values for fast propagation