A network administrator is investigating a report that a newly provisioned workstation cannot access an internal line-of-business portal at `portal.dev.company.local`. The administrator executes two command-line diagnostic queries from the workstation:
Query 1:
> nslookup portal.dev.company.local
Server: 192.168.1.1
Address: 192.168.1.1#53
** server can't find portal.dev.company.local: NXDOMAIN
Query 2:
> nslookup portal.dev.company.local 10.10.10.5
Server: 10.10.10.5
Address: 10.10.10.5#53
Name: portal.dev.company.local
Address: 10.10.10.45
Which of the following is the most likely root cause of this name resolution failure?
- The workstation is configured to use a default network gateway DNS proxy (192.168.1.1) that lacks internal domain forwarders, rather than the authoritative corporate DNS server (10.10.10.5).Answer
- BThe corporate DNS server at 10.10.10.5 is missing an AAAA host record for the internal web portal.
- CThe client workstation DNS resolver service requires TCP port 53 rather than UDP port 53 to perform standard single-answer hostname lookups.
- DThe nslookup utility output in Query 1 indicates that local DNS client resolver caching has corrupt authority SOA records.
Answer
The workstation is configured to use a default network gateway DNS proxy (192.168.1.1) that lacks internal domain forwarders, rather than the authoritative corporate DNS server (10.10.10.5).
The correct option correctly identifies that the workstation's default DNS server configuration (192.168.1.1) points to a gateway or recursive resolver that lacks routing/forwarding rules for the private domain `.company.local`. Explicitly supplying the target DNS server IP `10.10.10.5` in the second command successfully resolves the address to `10.10.10.45`, demonstrating that the internal DNS server and record are healthy.
Step-by-Step Solution
Key Concept
DNS Server Targeting and Resolver Misconfiguration