300-445 Question 121
Select 2Your organization is experiencing intermittent connectivity issues when accessing critical internal applications hosted on a private domain. Upon investigation, you discover that certain DNS queries are failing, resulting in delayed responses. You suspect the issue is related to the configuration of your DNS infrastructure. Which of the following actions should you take to troubleshoot and resolve the problem? (Choose two)
- A
Verify that the DNS servers configured on the clients are reachable and responding to queries.
- B
Inspect the TTL (Time-To-Live) values of the DNS records to ensure they are configured for optimal caching behavior.
- C
Disable DNSSEC (DNS Security Extensions) to reduce query latency.
- D
Check if the DNS forwarders or root hints are properly configured on your internal DNS servers.
- E
Reconfigure the clients to use public DNS servers instead of internal DNS servers.
Show answer and explanation
Correct answers: A, D
Explanation
Intermittent connectivity issues related to DNS are often caused by misconfigurations in the DNS infrastructure. Verifying the reachability of DNS servers ensures that clients can communicate with the servers, while checking the configuration of DNS forwarders or root hints ensures proper query resolution. These steps address the root cause of DNS failures without compromising security or operational requirements.
- A. Correct.
Verifying the reachability and responsiveness of DNS servers ensures that clients can successfully resolve domain names. If the servers are unreachable or unresponsive, DNS queries will fail.
- B. Incorrect.
Reviewing the TTL values is important for managing DNS caching, but it is unlikely to cause intermittent query failures. This step is more relevant for performance tuning than troubleshooting connectivity issues.
- C. Incorrect.
Disabling DNSSEC is not recommended as it compromises DNS security. DNSSEC is unlikely to be the root cause of intermittent failures unless a specific misconfiguration exists, which should be investigated separately.
- D. Correct.
Improper configuration of DNS forwarders or root hints on internal DNS servers can lead to incomplete or failed query resolutions. This is a common issue that can cause intermittent failures.
- E. Incorrect.
Reconfiguring clients to use public DNS servers bypasses the internal DNS infrastructure but risks exposing private domain queries to external systems. This is not a recommended approach for resolving issues with internal applications.