300-445 Question 126
Single answerAn enterprise network is experiencing intermittent connectivity issues with its internal applications. After initial troubleshooting, it is determined that the issue is related to the DNS system. The DNS servers are configured for redundancy, but some users are still unable to resolve hostnames during failover scenarios. Which of the following actions would most likely resolve this issue?
- A
Ensure that all DNS servers are added to the clients' resolver configuration.
- B
Increase the Time-to-Live (TTL) value for DNS records on the authoritative DNS server.
- C
Configure the DNS client devices to use a single, primary DNS server only.
- D
Enable DNS server logging to identify and resolve potential misconfigurations.
Show answer and explanation
Correct answer: A
Explanation
The issue stems from DNS clients not being able to fail over to alternate DNS servers, indicating that their resolver configurations are incomplete. Adding all available DNS servers to the clients' resolver configuration ensures that alternate servers can be used when the primary server is unavailable, thereby resolving the intermittent connectivity issue.
- A. Correct.
Ensuring that all DNS servers are added to the clients' resolver configuration allows devices to fail over to an alternate DNS server if the primary server becomes unavailable. This directly addresses the failover issue.
- B. Incorrect.
Increasing the TTL value for DNS records reduces the frequency of DNS queries but does not address the failover issue, as it would not impact client resolver configurations.
- C. Incorrect.
Configuring DNS clients to use a single, primary DNS server eliminates redundancy and increases the likelihood of downtime in case of server failure, which is counterproductive.
- D. Incorrect.
Enabling DNS server logging can help diagnose issues but does not directly resolve the failover problem.