A network technician executes a command-line DNS query on a workstation to troubleshoot host resolution. The technician receives the following terminal output:
text
Server: resolver.lab.corp
Address: 192.168.1.254
Non-authoritative answer:
Name: fileserver.lab.corp
Address: 10.1.50.12
Which of the following statements correctly interprets the 'Non-authoritative answer' header in this CLI output?
- The responding DNS server provided the IP address from its local cache rather than holding the master zone file for the domain.Cevap
- BThe client workstation resolved the hostname using its local hosts file because the configured DNS server was unreachable.
- CThe DNS lookup failed because an AAAA record query was submitted instead of a canonical name CNAME record request.
- DThe DNS request was transmitted over UDP port 53 instead of TCP port 53 required for authoritative zone responses.
Cevap
The responding DNS server provided the IP address from its local cache rather than holding the master zone file for the domain.
The 'Non-authoritative answer' designation indicates that the DNS server fulfilling the query obtained the host mapping from its cached memory (or via recursive queries to other name servers) rather than maintaining the original authoritative zone database for the domain.
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Anahtar Kavram
Interpreting nslookup and DNS command-line utility outputs