A security operations analyst is investigating why a corporate workstation cannot reach a newly provisioned internal web application at `api.corp.local`. The analyst executes two diagnostic diagnostic commands from the client terminal:
text
C:\Users\Analyst> nslookup api.corp.local
Server: router.home.gateway
Address: 192.168.1.1
Non-authoritative answer:
Name: api.corp.local
Address: 203.0.113.45
C:\Users\Analyst> dig @10.20.4.5 api.corp.local A +short
10.20.4.200
Based on the output above, which of the following is the most likely root cause of this name resolution discrepancy?
- The client network interface is statically configured to query an improper local gateway address rather than the internal corporate DNS server.Cevap
- BThe authoritative DNS server at 10.20.4.5 is missing an AAAA resource record for api.corp.local, causing resolution to fail over IPv6.
- CAn intermediate network firewall is blocking UDP port 53 traffic between the workstation and the local gateway at 192.168.1.1.
- DThe DNS response payload exceeds 512 bytes, forcing the client to fail over to TCP port 53 without receiving a truncation flag.
Cevap
The client network interface is statically configured to query an improper local gateway address rather than the internal corporate DNS server.
The nslookup output indicates that the workstation's default DNS server is configured as 192.168.1.1, which returns an incorrect/external IP address (203.0.113.45). When the analyst explicitly queries the corporate DNS server at 10.20.4.5 using dig, it returns the correct internal IP address (10.20.4.200). This proves the internal DNS server is working properly, but the workstation is querying the wrong DNS server due to an incorrect network adapter DNS configuration.
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DNS Client Resolver Configuration & Targeted CLI Diagnostics
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