SK0-005 Question #384: Real Exam Question with Answer & Explanation

Question

A security analyst completed a port scan of the corporate production-server network. Results of the scan were then provided to a systems administrator for immediate action. The following table represents the requested changes: The systems administrator created local firewall rules to block the ports indicated above. Immediately, the service desk began receiving calls about the internet being down. The systems administrator then reversed the changes, and the internet became available again. Which of the following ports on DNSSrv must remain open when the firewall rules are reapplied?

Options

• A20
• B21
• C22
• D23
• E53

Explanation

Port 53 is the standard port for DNS (Domain Name System) queries and responses. DNS is a 192.0.2.1) and vice versa. DNS is essential for internet connectivity, as it allows users and applications to access websites and other online resources by using human-readable names instead of numerical addresses. The DNSSrv server is a DNS server that provides name resolution for the corporate network. If port 53 is blocked on this server, it will not be able to communicate with other DNS servers or clients, and the name resolution will fail. This will prevent users from accessing any websites or online services that rely on domain names, such as web browsers, email clients, or cloud applications. Therefore, port 53 must remain open on DNSSrv to allow DNS traffic to flow.

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