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Zorluk: OrtaDNS Infrastructure and Record Types

A client workstation with an empty local DNS cache needs to access an internal corporate host at host.finance.example.com. The workstation sends a DNS query to its configured recursive DNS server, which subsequently performs iterative lookups to resolve the fully qualified domain name (FQDN). In what order do the steps of this DNS name resolution process occur from initial request to final IP resolution?

  1. 1The client stub resolver sends a recursive query for host.finance.example.com to the local recursive DNS server.
  2. 2The local recursive DNS server queries a Root Name Server and receives a referral to the .com Top-Level Domain (TLD) name servers.
  3. 3The local recursive DNS server queries the .com TLD name server and receives a referral to the authoritative name server for example.com.
  4. 4The local recursive DNS server queries the authoritative name server for example.com requesting the A record for host.finance.example.com.
  5. 5The authoritative name server responds with the requested IP address, which the local recursive DNS server caches and returns to the client stub resolver.

Cevap

The correct sequence starts with the client issuing a recursive DNS query to the local DNS server, followed by iterative queries from the local server to a Root Name Server, the .com TLD Name Server, and the authoritative example.com Name Server, concluding with the authoritative server returning the IP address to the local server, which caches and forwards it to the client.
The DNS resolution sequence follows a top-down hierarchical flow when resolving an uncached hostname: 1) The client stub resolver sends a recursive query to the configured local resolver. 2) The local resolver queries a Root Name Server to find the appropriate TLD server (.com). 3) The local resolver queries the .com TLD server to find the authoritative server for example.com. 4) The local resolver queries the authoritative server for host.finance.example.com. 5) The authoritative server returns the IP address answer to the local resolver, which caches the result and returns it to the client stub resolver.

Adım Adım Çözüm

1
Client initiates request
The client stub resolver sends a recursive query to the local DNS resolver.
The client requires host name resolution and delegates the work to its local recursive server.
2
Query Root Name Server
The local resolver queries a Root Name Server and receives NS records for .com TLD servers.
Iterative resolution begins at the root level of the DNS hierarchy.
3
Query TLD Name Server
The local resolver queries the .com TLD server and receives NS records for example.com authoritative servers.
TLD servers hold delegation references for registered domain names within their domain.
4
Query Authoritative Name Server
The local resolver queries the authoritative DNS server for host.finance.example.com.
The authoritative server holds the actual resource records (such as A/AAAA records) for the zone.
5
Return and cache answer
The authoritative server returns the IP address; the local DNS server caches the result and sends the final answer to the client.
This completes the recursive lookup request and populates the resolver cache to speed up subsequent queries.

Anahtar Kavram

DNS Recursive vs. Iterative Resolution Hierarchy
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Konular

DNS Infrastructure and Record Types

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