300-445 Question 124
Select 2An enterprise network's DNS servers are experiencing intermittent failures, causing delays in resolving internal and external domain names. As part of the network assurance strategy, you need to implement a solution to improve DNS resolution reliability and fault tolerance. Which two actions should you take?
- A
Implement DNS caching on client devices to reduce the dependency on DNS servers.
- B
Deploy multiple DNS servers across different geographic locations and configure failover mechanisms.
- C
Enable DNSSEC (DNS Security Extensions) on all DNS servers to secure DNS queries.
- D
Configure forwarding on internal DNS servers to external public DNS resolvers.
- E
Set up split-horizon DNS to separate internal and external DNS queries.
Show answer and explanation
Correct answers: B, D
Explanation
To improve DNS resolution reliability and fault tolerance, deploying multiple DNS servers with failover ensures redundancy, while configuring forwarding provides an additional layer of fallback to external resolvers. These actions reduce the likelihood of DNS resolution failures within the enterprise network.
- A. Incorrect.
Implementing DNS caching on client devices can reduce DNS query load, but it does not directly address fault tolerance or ensure reliability in the event of DNS server failures.
- B. Correct.
Deploying multiple DNS servers with failover mechanisms improves reliability and ensures that DNS resolution continues even if one server fails.
- C. Incorrect.
Enabling DNSSEC improves the security of DNS queries but does not directly address DNS server reliability or fault tolerance.
- D. Correct.
Configuring forwarding on internal DNS servers to public DNS resolvers provides redundancy and ensures DNS resolution if internal servers fail.
- E. Incorrect.
Split-horizon DNS is used for separating internal and external queries, which is useful for security and traffic separation but does not directly address reliability or fault tolerance.