N10-005 Question #800: Real Exam Question with Answer & Explanation

Question

Options

• ASource. 192.168.1.100; Source Port: Any; Destination: 192.168.3.3; Destination Port:80; Action: Permit
• BSource. 192.168.1.100; Source Port:80; Destination: 192.168.3.3; Destination Port:80; Action: Permit
• CSource. 192.168.3.3; Source Port:80; Destination: 192.168.1.100; Destination Port: Any; Action: Permit
• DSource. 192.168.3.3; Source Port:80; Destination: 192.168.1.100; Destination Port:80; Action: Permit
• ESource. 192.168.1.100; Source Port: Any; Destination: 192.168.3.3; Destination Port: Any; Action: Permit

Explanation

A host-based firewall ACL filtering inbound traffic must specify the source as the Development Server and the destination port as 80 (HTTP), with the source port set to any because clients use ephemeral high ports. Choice A correctly models this traffic flow.

Common mistakes.

• B. Setting source port to 80 is incorrect because port 80 is the well-known server port - the client (Development Server) will use a random ephemeral source port, not port 80.
• C. The source and destination IP addresses are reversed; this rule would permit traffic originating from the PC going to the Development Server, not the other way around.
• D. Both the source/destination IPs are reversed and the source port is incorrectly set to 80, making this rule match the wrong traffic direction entirely.
• E. Setting destination port to 'Any' is overly permissive and would allow the Development Server to connect to any port on the PC, violating the requirement to restrict access to only the HTTP port.

Concept tested. Host-based firewall ACL rule creation for HTTP

Reference. https://learn.microsoft.com/en-us/windows/security/operating-system-security/network-security/windows-firewall/rules

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