A network technician executes `nslookup -type=TXT _dmarc.example.com` to verify an email authentication policy record. The command returns the following terminal output:
Server: UnKnown
Address: 192.168.1.2
Non-authoritative answer:
_dmarc.example.com text = "v=DMARC1; p=reject;"
Based on this command-line output, which of the following statements correctly interprets the diagnostic result?
- The record data was successfully retrieved from a local caching DNS resolver rather than the authoritative DNS server for example.com.Cevap
- BThe query failed completely because the local DNS server host name could not be resolved and is displayed as 'UnKnown'.
- CThe lookup returned invalid data because DMARC policies must be published using A records rather than TXT records.
- DThe query was rejected because the nslookup utility attempted to query the DNS server over TCP port 25 instead of UDP port 53.
Cevap
The record data was successfully retrieved from a local caching DNS resolver rather than the authoritative DNS server for example.com.
The 'Non-authoritative answer' output header signifies that the server responding to the query (192.168.1.2) obtained the record via recursive resolution or local cache rather than directly holding the authoritative zone files for example.com. The TXT query successfully returned the expected DMARC record.
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Anahtar Kavram
Interpreting nslookup output headers and non-authoritative DNS lookup results