CompTIA Updated N10-009 Exam Questions and Answers by claudia

For a secure 802.1X design that includes BYOD access to a trusted wireless network, the engineer should implement NAC (Network Access Control). In the Network+ (N10-009) objectives, 802.1X provides authentication (commonly via EAP to a RADIUS server), but NAC expands this by enforcing policy-based access decisions—such as device posture checks, user/device identity validation, and dynamic assignment to the appropriate VLAN/role. With BYOD, the organization often needs to confirm whether devices meet requirements (OS version, encryption, security software) and then grant the correct level of access (full, limited, or quarantine/remediation). NAC is the architecture that ties these controls together in a scalable way for wireless networks.

An ACL can restrict traffic after a device connects, but it doesn’t perform authentication/posture assessment. MAC filtering is weak because MAC addresses can be spoofed and it does not provide strong identity assurance. Port security is mainly a wired switch control (limiting MAC addresses per port) and is not the right control set for secure BYOD wireless access. NAC best matches the requirement of secure, policy-driven 802.1X BYOD access.

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RPO (Recovery Point Objective) describes a data recovery goal by defining the maximum acceptable amount of data loss measured in time. For example, an RPO of 4 hours means the organization must be able to restore data to a point no more than four hours before the outage—so backups, replication, or snapshots must occur frequently enough to meet that target. In Network+ (N10-009) operations objectives, disaster recovery and business continuity concepts include understanding recovery metrics and how they influence backup strategies, replication design, and service resilience planning. RPO specifically answers: “How much data can we afford to lose?”

By contrast, MTBF (Mean Time Between Failures) is a reliability metric describing how often failures occur. MTTR (Mean Time To Repair/Recover) measures how long it takes to restore a system after failure, which is more aligned with service restoration time rather than data loss. BCP (Business Continuity Plan) is the overall plan/process for keeping critical business functions running during disruptions; it is not a single data recovery metric. Therefore, RPO is the correct term for a data recovery goal.

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The correct answer is B. Port 25 . In CompTIA Network+ N10-009, candidates are expected to know common networking protocols, their purposes, and their associated port numbers. SMTP, or Simple Mail Transfer Protocol, uses TCP port 25 and is primarily responsible for sending email messages between mail servers. When one organization’s mail server needs to deliver a message to another organization’s mail server, SMTP commonly performs that server-to-server transfer using port 25.

The other options are associated with different services. Port 21 is used by FTP for command/control communication during file transfers. Port 53 is used by DNS for name resolution, translating domain names into IP addresses. Port 69 is used by TFTP, a simplified file transfer protocol often associated with lightweight network device file transfers, such as firmware or configuration files.

For Network+ exam purposes, it is important to distinguish SMTP from email retrieval protocols. POP3 uses port 110 , and IMAP uses port 143 for client mail retrieval, while SMTP is used for sending and relaying email. Therefore, the port used to transfer data between mail exchange servers is TCP 25 .

Servers shut down due to overheating, not loss of electrical power. Although UPS units had battery life, without cooling systems (HVAC/air conditioning) running on backup power, server rooms overheated. Backup power for air-conditioning is essential in data center design.

B. Door locks are unrelated to server shutdown.

C. Increasing UPS capacity won’t help cooling.

D. IoT thermostats may monitor temperature but won’t prevent overheating.

References (CompTIA Network+ N10-009):

Domain: Network Infrastructure — Environmental controls, power redundancy, HVAC systems.