An average of one out of three users in a company cannot reach the company website. A Linux administrator determines that one of the three website servers is down. The administrator inspects the DNS…

Question

Options

• AThe DNS configuration is missing corresponding AAAA records and PTR records, and this is
• BThe administrator has incorrectly configured the DNS server to be an iterative resolver instead of
• COne of the DNS records has not been signed with a DNSSEC-supported key, and this is causing
• DDNS returns all three records in a different order each time, and the browser typically uses the

• A
  9% (6)
• B
  2% (1)
• C
  5% (3)
• D
  85% (55)

Explanation

The DNS configuration shows three A records for the same hostname pointing to three different server IPs - a classic round-robin DNS load balancing setup. DNS round-robin works by returning all three records in a rotating order with each query. Browsers and clients typically attempt to connect to the first IP address returned. When the down server's IP appears first in the returned list (which happens approximately 1 in 3 queries), those users fail to reach the site - matching the observed symptom of 'one out of three users' experiencing issues. The solution would be to remove the A record pointing to the downed server until it is restored. The other options describe AAAA/PTR record misconfigurations, resolver configurations, and DNSSEC issues, none of which match the described symptom.

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