SK0-004 · Question #488
A user is unable to connect to the company's intranet server by FQDN, but can connect by IP address. Other users are not having a problem. An administrator verifies that the user can successfully…
The correct answer is D. Examine the hosts file. When nslookup resolves the FQDN correctly and the DNS client cache has already been flushed but the problem persists for a single user, an incorrect entry in the local hosts file is the most likely cause.
Question
A user is unable to connect to the company's intranet server by FQDN, but can connect by IP address. Other users are not having a problem. An administrator verifies that the user can successfully ping the server by IP address and can properly resolve the FQDN using nslookup. The problem is persisting after running ipconfig /flushdns. Which of the following should the administrator do NEXT?
Options
- AExamine the lmhost file.
- BFlush the cache on the DNS server.
- CFlush the cache on the WINS server.
- DExamine the hosts file.
How the community answered
(35 responses)- A6% (2)
- B3% (1)
- C6% (2)
- D86% (30)
Why each option
When nslookup resolves the FQDN correctly and the DNS client cache has already been flushed but the problem persists for a single user, an incorrect entry in the local hosts file is the most likely cause.
The lmhosts file is used for NetBIOS over TCP/IP name resolution, not for FQDN-based DNS resolution, so it would not affect this scenario.
Flushing the DNS server cache is unnecessary because nslookup already confirms that the DNS server is resolving the FQDN correctly.
WINS is a NetBIOS name resolution service and does not participate in FQDN or DNS-based name resolution.
The Windows name resolution process checks the local hosts file before querying DNS, meaning a stale or incorrect entry there overrides DNS even when the DNS server is functioning correctly. Since nslookup bypasses the hosts file and resolves successfully, and ipconfig /flushdns already eliminated the client-side DNS cache, the hosts file is the remaining local override that could explain a single-user-specific failure. Removing or correcting the bad entry in the hosts file would restore normal FQDN resolution.
Concept tested: Windows name resolution order - hosts file override
Source: https://learn.microsoft.com/en-us/windows-server/networking/dns/troubleshoot/troubleshoot-dns-client
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