A network technician is diagnosing host reachability issues and executes a query using the `dig` command-line utility on a Linux workstation to verify name resolution for `app.corp.local`:
text
$ dig app.corp.local
; <<>> DiG 9.18.1-1-Debian <<>> app.corp.local
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 41205
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1
;; QUESTION SECTION:
;app.corp.local. IN A
;; AUTHORITY SECTION:
corp.local. 3600 IN SOA ns1.corp.local. admin.corp.local. 2026072601 7200 3600 1209600 3600
;; Query time: 12 msec
;; SERVER: 192.168.10.5#53(192.168.10.5)
Which of the following describes the root cause of the name resolution failure based on the command output?
- The domain zone exists, but no IPv4 host (A) record is configured for the requested hostname.Answer
- BThe designated DNS server at 192.168.10.5 failed to respond to the UDP query within the timeout threshold.
- CThe lookup utility requested an IPv6 host (AAAA) record instead of an IPv4 host (A) record.
- DOutbound UDP port 53 traffic is being blocked by a local network firewall.
Answer
The target domain zone exists on the authoritative server, but no IPv4 host (A) record is defined for the requested hostname.
In `dig` utility output, a header status of `NOERROR` paired with `ANSWER: 0` and an authoritative `SOA` record returned in the `AUTHORITY` section indicates a NODATA condition. This occurs when the DNS server is reachable and holds the domain zone, but no resource record matching the requested name and record type exists.
Step-by-Step Solution
Key Concept
DNS NODATA Response and Dig Output Interpretation
Estimated Time:1m 30s