N10-009 Practice Test 27 — 15 Questions

Question 1

A network administrator is preparing to upgrade the firmware on a critical router. Which document should the administrator consult to understand the steps required to minimize downtime and ensure a successful upgrade?

Accepted Answer

Change management plan. The change management plan documents the approved procedures, rollback steps, and communication protocols for performing maintenance on critical infrastructure. Consulting this plan ensures the administrator follows the organization's predefined steps to minimize downtime and mitigate risks during the firmware upgrade.

Answer

SLA

Answer

Network diagram

Answer

Baseline performance report

Question 2

A network administrator needs to allow multiple VLANs to traverse a single link between two switches. Which configuration must be applied on the switch ports?

Accepted Answer

Trunk port. A trunk port is configured to carry traffic for multiple VLANs over a single link by tagging frames with IEEE 802.1Q VLAN identifiers. This allows the switch to distinguish which VLAN each frame belongs to, enabling inter-switch VLAN connectivity without requiring separate physical links per VLAN.

Answer

Access port

Answer

Hybrid port

Answer

Routed port

Question 3

A network administrator is configuring Quality of Service (QoS) on a router to prioritize voice traffic. Which of the following fields should be used to mark packets for classification and prioritization?

Accepted Answer

DSCP. DSCP (Differentiated Services Code Point) is the correct field because it is a 6-bit value in the IP header used to mark packets for QoS classification and prioritization, as defined in RFC 2474. Voice traffic typically uses DSCP EF (Expedited Forwarding, value 46) to ensure low latency and jitter, making it the standard choice for QoS marking on routers.

Answer

Source IP address

Answer

Source port number

Answer

MAC address

Question 4

Users in VLAN 10 cannot obtain IP addresses from the DHCP server located in VLAN 20. The router interface for VLAN 10 has an ip helper-address 192.168.20.5 command configured, and users can ping the DHCP server IP (192.168.20.5) from the router. However, users receive APIPA addresses. What is the most likely cause?

Accepted Answer

The DHCP server does not have a scope configured for the 192.168.1.0/24 subnet (VLAN 10). The ip helper-address command on the router correctly forwards DHCPDISCOVER broadcasts from VLAN 10 to the DHCP server at 192.168.20.5. Since users can ping the server from the router, Layer 3 connectivity exists. However, the DHCP server must have a scope (or address pool) for the subnet of the requesting clients (192.168.1.0/24) to offer an IP address; without it, the server ignores the request, and clients fall back to APIPA (169.254.x.x).

Answer

The router's ip helper-address is configured on the wrong interface

Answer

The switch port connecting users is configured as a trunk instead of an access port

Answer

The router's ACL is blocking DHCP offers from the server

Question 5

A network administrator is configuring a new switch in a production environment. The switch must be managed remotely. Which of the following should be configured on the switch's management interface?

Accepted Answer

Default gateway. The default gateway is required for remote management because the management interface (often a virtual interface like VLAN 1 or a dedicated management VLAN) needs a route to reach devices on different subnets. Without a default gateway, the switch can only be accessed from hosts within the same subnet, making remote management impossible across routed networks.

Answer

Spanning tree priority

Answer

VLAN 1 membership

Answer

Port security

Question 6

A network administrator is about to implement a QoS policy on a core router. According to change management best practices, which step should the administrator perform FIRST to ensure the policy can be reverted if it causes unexpected issues?

Accepted Answer

Back up the current configuration to an external TFTP or SCP server.. Option B is correct because, under change management best practices, the first step before implementing any change is to create a reliable backup of the current configuration to an external server (e.g., TFTP, SCP, FTP). This ensures that if the QoS policy causes unexpected issues such as traffic drops or misclassification, the administrator can restore the original configuration exactly as it was, even if the router reboots or the running-config is lost. Saving to startup-config (Option A) would overwrite the known-good baseline, making reversion impossible without a separate backup.

Answer

Save the running configuration to the startup configuration.

Answer

Test the QoS policy in a lab environment.

Answer

Schedule a maintenance window and notify the help desk.

Question 7

A network administrator is designing a Layer 2 network with redundant links between switches. Which protocol should be implemented to prevent loops in the network?

Accepted Answer

STP (Spanning Tree Protocol). STP (Spanning Tree Protocol) is the correct choice because it is specifically designed to prevent Layer 2 loops in networks with redundant links. It achieves this by placing redundant switch ports into a blocking state, creating a loop-free logical topology while maintaining physical redundancy for failover.

Answer

OSPF (Open Shortest Path First)

Answer

VRRP (Virtual Router Redundancy Protocol)

Answer

LACP (Link Aggregation Control Protocol)

Question 8

A network administrator is documenting the network topology. Which of the following tools is best suited for creating a diagram that shows the logical connections between network devices?

Accepted Answer

Microsoft Visio. Microsoft Visio is the correct tool because it is specifically designed for creating professional network topology diagrams, including logical connections between devices. Unlike general-purpose tools, Visio provides network-specific shapes, templates, and layering capabilities that accurately represent logical relationships such as VLANs, subnets, and routing paths.

Answer

Microsoft Excel

Answer

SNMP

Answer

Notepad

Question 9

A network administrator is deploying a wireless network in a warehouse environment with many metal racks. Clients using 802.11ac report strong signal strength but very low throughput. What is the most likely cause?

Accepted Answer

Multipath interference caused by signal reflections off metal surfaces. In a warehouse with many metal racks, 802.11ac signals reflect off the metal surfaces, creating multiple signal paths that arrive at the receiver at slightly different times. This multipath interference causes phase cancellation and intersymbol interference, which degrades the signal-to-noise ratio and forces the use of lower modulation and coding schemes (MCS), drastically reducing throughput despite strong RSSI.

Answer

Co-channel interference from neighboring access points

Answer

The encryption method is set to WEP, which limits throughput

Answer

Too many clients are connected to the same access point

Question 10

A network administrator is investigating reports of slow network performance. Which tool should the administrator use to capture and analyze individual packets to identify the cause of the latency?

Accepted Answer

D. Option D is correct because a packet analyzer (e.g., Wireshark, tcpdump) captures and decodes individual packets, allowing the administrator to inspect frame-level details, identify retransmissions, TCP window scaling issues, or application-layer delays that cause latency. Unlike aggregate monitoring tools, packet analysis provides the granularity needed to pinpoint the exact cause of slow performance.

Answer

A

Answer

B

Answer

C

Question 11

A network administrator is installing cable in a plenum space (an area used for air circulation, such as above a drop ceiling). Which cable type is required by most building codes for such an installation?

Accepted Answer

Plenum-rated cable. Plenum-rated cable is required by most building codes (e.g., NFPA 70, National Electrical Code) for installation in plenum spaces because it is constructed with fire-retardant materials, such as FEP or PFA, that produce minimal smoke and are self-extinguishing. This prevents toxic fumes and flames from spreading through air-handling areas, ensuring safety in case of a fire. Standard PVC-jacketed cable would release hazardous smoke and support flame propagation, making it illegal in plenum spaces.

Answer

PVC-jacketed cable

Answer

Riser-rated cable

Answer

Low Smoke Zero Halogen (LSZH) cable

Question 12

A network engineer needs to deploy a new wireless network in a large office with many cubicles. The goal is to provide high throughput and support multiple simultaneous users. Which IEEE standard should be implemented?

Accepted Answer

802.11ac. 802.11ac (Wi-Fi 5) operates exclusively in the 5 GHz band, uses wider 80 MHz or 160 MHz channels, and supports MU-MIMO (Multi-User Multiple Input Multiple Output) to deliver high throughput and efficient handling of multiple simultaneous users in a dense office environment. This makes it the best choice among the options for a modern, high-capacity wireless deployment.

Answer

802.11n

Answer

802.11b

Answer

802.11g

Question 13

A network administrator needs to analyze bandwidth utilization and application traffic patterns on a WAN link. The administrator requires detailed flow-level data, including source/destination IP addresses, ports, and protocol. Which technology should be deployed?

Accepted Answer

NetFlow. NetFlow is the correct choice because it provides detailed flow-level data, including source/destination IP addresses, ports, and protocol information, which is essential for analyzing bandwidth utilization and application traffic patterns on a WAN link. Unlike simpler monitoring tools, NetFlow captures metadata about each network flow, allowing administrators to identify which applications and hosts are consuming bandwidth.

Answer

SNMP

Answer

Syslog

Answer

ICMP

Question 14

A network administrator needs to ensure that network device configurations are automatically backed up to a central server. Which protocol is commonly used for secure file transfer of configurations?

Accepted Answer

SFTP. SFTP (SSH File Transfer Protocol) is the correct choice because it provides encrypted, secure file transfers over an SSH session, making it ideal for backing up sensitive network device configurations to a central server. Unlike TFTP or FTP, SFTP ensures both authentication and data confidentiality, which is critical for network operations.

Answer

TFTP

Answer

FTP

Answer

HTTP

Question 15

A network administrator needs to ensure that only authorized devices can connect to the wired network. Each user must authenticate using their domain credentials. Which of the following should be implemented?

Accepted Answer

802.1X with EAP-TLS. 802.1X with EAP-TLS is correct because it provides port-based network access control that requires each user to authenticate using their domain credentials (via a RADIUS server) before the switch port is opened for traffic. EAP-TLS uses mutual authentication with digital certificates, ensuring only authorized devices and users gain access to the wired network.

Answer

MAC filtering

Answer

WPA2-PSK

Answer

Port security