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Difficulty: EasyDNS Infrastructure and Record Types

A client computer on an enterprise network attempts to resolve the domain name www.example.com for the first time without any local cached records. Place the steps of the DNS lookup process in the correct chronological order from the initial request to receiving the IP address.

  1. 1The client stub resolver checks its local DNS cache and queries the local recursive DNS server.
  2. 2The local recursive DNS server queries a Root Name Server to locate the Top-Level Domain (TLD) server.
  3. 3The local recursive DNS server queries the .com TLD server to obtain the authoritative name server for example.com.
  4. 4The local recursive DNS server queries the authoritative name server for the A record of www.example.com.
  5. 5The authoritative name server returns the IP address to the recursive resolver, which caches and forwards it to the client.

Answer

The correct sequence starts with the client querying its local cache and local recursive DNS server, followed by the recursive server querying the Root Name Server, the TLD Name Server, and finally the Authoritative Name Server before returning the IP address to the client.
The standard DNS resolution flow moves from client stub resolver to local recursive resolver, then hierarchically traverses the DNS tree: Root Name Server -> TLD Name Server -> Authoritative Name Server, before caching and returning the IP address to the requesting host.

Step-by-Step Solution

1
Initiate query locally
Client stub resolver checks cache and sends query to local recursive resolver.
Local resolution reduces unnecessary network traffic if the mapping is already known.
2
Query Root Server
Recursive resolver contacts a Root Name Server.
Root servers direct queries to the correct Top-Level Domain server (e.g., .com).
3
Query TLD Server
Recursive resolver contacts the TLD Server.
TLD servers maintain delegation records (NS records) pointing to the domain's authoritative name servers.
4
Query Authoritative Server
Recursive resolver requests the specific host record from the Authoritative Name Server.
Authoritative servers hold the actual mapping records (A/AAAA) for hostnames in their zone.
5
Return result to client
The IP address is cached by the recursive resolver and delivered to the client stub resolver.
Completes the DNS lookup lifecycle and enables network communication to the IP address.

Key Concept

DNS Recursive Resolution Hierarchy
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Topics

DNS Infrastructure and Record Types

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