CompTIA N10-009 Actual Questions

When a switch is improperly connected to a network, it can cause widespread connectivity issues, especially if there’s a misconfiguration in VLAN settings. A Native VLAN mismatch occurs when two switches connected via a trunk link have different native VLANs configured for untagged traffic. This can cause traffic to be sent to the wrong VLAN or dropped, resulting in connectivity loss for users.

Scenario Analysis: The intern likely connected the switch without ensuring that the trunk port’s native VLAN matched the existing network configuration. This is a common issue in Cisco-based networks when trunk links are misconfigured.

Why not VTP update? VLAN Trunking Protocol (VTP) updates propagate VLAN configurations across switches. While a VTP misconfiguration could cause issues, it’s less likely to immediately disrupt connectivity for many users unless the VTP server deleted critical VLANs, which is not implied here.

Why not Port security issue? Port security restricts access based on MAC addresses, typically affecting individual ports, not causing widespread outages.

Why not LLDP misconfiguration? Link Layer Discovery Protocol (LLDP) is used for device discovery, and misconfiguration is unlikely to cause a broad loss of connectivity.

The correct answer is B. tcpdump. According to the CompTIA Network+ N10-009 objectives, troubleshooting network connectivity often requires validating whether traffic is actually reaching a device. tcpdump is a command-line packet analyzer that captures and displays packets being transmitted or received on a network interface in real time. This makes it the most effective tool among the options for verifying whether a server is receiving network traffic.

When using tcpdump, a technician can observe incoming packets, identify source and destination IP addresses, check protocols, and determine whether expected traffic (such as HTTP, ICMP, or DNS) is reaching the server. This directly helps isolate issues such as firewall blocking, routing problems, or application-layer failures.

The other options serve different purposes. traceroute is used to identify the path packets take across a network and diagnose routing issues, but it does not confirm packet arrival at the server interface. nslookup is used to query DNS servers for name resolution and is unrelated to packet capture. arp is used to view or manipulate the Address Resolution Protocol table, which maps IP addresses to MAC addresses, but it does not show live traffic flow.

Therefore, tcpdump is the most appropriate tool for confirming whether the server is receiving network traffic.

The correct answer is Spanning Tree because broadcast storms are typically caused by Layer 2 switching loops in Ethernet networks. According to the CompTIA Network+ (N10-009) objectives under switching concepts, the Spanning Tree Protocol (STP) is specifically designed to prevent loops in networks that have redundant switch connections.

In a Layer 2 environment, switches forward broadcast frames out all ports except the one on which they were received. If redundant paths exist without STP, frames can circulate indefinitely, creating a broadcast storm. This results in excessive traffic, high CPU utilization on switches, MAC address table instability, and significant network performance degradation.

STP prevents this by logically blocking redundant paths while maintaining them as backups. If the active path fails, STP recalculates and activates a previously blocked path, preserving redundancy without loops.

The other options—EIGRP and BGP (routing protocols) and CDP and LLDP (device discovery protocols)—do not prevent Layer 2 loops.

Therefore, configuring Spanning Tree Protocol is the appropriate solution to mitigate broadcast storms.

802.1Q tagging, also known as VLAN tagging, is used to identify VLANs on a trunk link between switches. This allows the switches to transfer data for multiple VLANs (or networks) over a single physical connection. This method ensures that traffic from different VLANs is properly separated and managed across the network.References: CompTIA Network+ study materials.