CompTIA Updated N10-009 Exam Questions and Answers by teodor

The CompTIA troubleshooting methodology includes steps like identifying the problem, establishing a theory of probable cause, testing the theory, creating a plan of action, implementing the solution, verifying functionality, and documenting findings. Establishing a theory involves analyzing the problem and considering possible causes, often by systematically checking each level of the OSI model (Physical, Data Link, Network, etc.) to pinpoint the root cause.

Why not Implement the solution? This step involves applying the fix, not analyzing the OSI model.

Why not Create a plan of action? This step focuses on planning the solution, not diagnosing the cause.

Why not Verify functionality? This step confirms the solution worked, not analyzing the OSI model.

A rogue DHCP server occurs when an unauthorized or misconfigured DHCP server assigns incorrect IP addresses, default gateways, or DNS settings to clients.

•In this scenario:

•The user can ping the gateway, meaning local network communication is working.

•However, they cannot access network resources, which suggests incorrect IP configuration (likely due to a rogue DHCP server assigning the wrong gateway or DNS).

•Why not the other options?

•VLAN hopping (A): This is an attack that exploits VLAN configurations to gain access to unauthorized VLANs. It would not typically cause multiple users to lose network access.

•Distributed DoS (C): A DDoS attack floods a network or service with traffic, but this issue is more likely misconfigured IP settings than an actual attack.

•Evil twin (D): This refers to a fraudulent Wi-Fi network mimicking a legitimate one. Since the users are on a wired network (ipconfig output checked), this is not applicable.

A transceiver is the correct answer because it is the Layer 1 (Physical Layer) component that physically terminates and converts fiber-optic signals on an SFP-capable switch. In CompTIA Network+ N10-009 objectives, transceivers—such as SFP, SFP+, QSFP, and QSFP+ modules—are explicitly identified as physical interface components that handle signal transmission and reception. These modules convert electrical signals from the switch into optical signals for fiber cabling (and vice versa), enabling communication over different media types and distances.

A modem is also a Layer 1 device, but its purpose is to modulate and demodulate signals for WAN technologies such as DSL or cable—it does not terminate fiber connections on switches. An Ethernet NIC provides network access for end devices like computers and servers and typically terminates copper Ethernet, not modular fiber interfaces on switches. A repeater regenerates and amplifies signals to extend cable distances but does not provide fiber termination or media conversion at a switch port.

According to Network+ standards, SFP transceivers are essential for flexible network design, allowing administrators to select appropriate fiber types (single-mode or multi-mode), wavelengths, and distances while remaining compliant with physical layer requirements.

The correct answer is Autonomous system path because BGP (Border Gateway Protocol) prevents routing loops by using the AS_PATH attribute. According to CompTIA Network+ (N10-009) objectives under routing protocols, BGP is a path vector protocol used to exchange routing information between autonomous systems (AS) on the internet.

When a BGP router advertises a route, it includes its autonomous system number (ASN) in the AS_PATH attribute. As the route passes through additional autonomous systems, each AS appends its own ASN to the path. If a BGP router receives a route advertisement that already contains its own ASN in the AS_PATH list, it recognizes this as a loop and rejects the route. This mechanism effectively prevents routing loops across large-scale networks such as the internet.

Option B (Peer autonomous system) refers to neighboring BGP routers but does not describe the loop prevention mechanism. Option C (Autonomous system length) relates to path selection metrics, as shorter AS_PATH lengths are generally preferred, but this is not the loop avoidance function itself. Option D (Public autonomous system) is not a loop prevention mechanism.

Therefore, BGP uses the AS_PATH attribute for loop avoidance.