100-150 Infrastructure Practice Test 3 — 15 Questions

Question 1

What is the primary purpose of a default gateway in an IP host configuration?

Accepted Answer

To act as an exit point for off-subnet traffic.. A default gateway is the router that a host sends packets to when the destination IP is not on the local subnet. It serves as the exit point for off-subnet traffic, allowing communication with external networks such as the internet or other subnets.

Answer

To resolve domain names to IP addresses.

Answer

To manage the assignment of dynamic IP addresses.

Answer

To filter incoming traffic from the internet.

Question 2

Which type of cabling is best suited for long-distance data transmission that requires high bandwidth and is immune to electromagnetic interference?

Accepted Answer

Single-mode Fiber. Fiber-optic cabling uses light pulses to transmit data, providing immense bandwidth over long distances without being affected by electromagnetic interference (EMI). This makes it superior to copper-based media for backbone connections. Understanding the differences between fiber and copper is crucial for planning infrastructure, especially in environments where cable runs exceed standard Ethernet limits or require high-speed data integrity across large facilities.

Answer

Unshielded Twisted Pair (UTP)

Answer

Coaxial Cable

Answer

Shielded Twisted Pair (STP)

Question 3

Refer to the exhibit. If a third device with a different MAC address is connected to this port, what will occur?

Accepted Answer

The port will transition to an err-disabled state.. The configuration specifies a maximum of 2 learned MAC addresses, with a violation mode of shutdown. When the limit is exceeded by a third device, the port will immediately transition to the err-disabled state. This is a vital security feature to prevent unauthorized devices from connecting to the switch and to mitigate MAC flooding attacks that could compromise the integrity of the Layer 2 network.

Answer

The port will remain active and log a syslog message.

Answer

The packet from the third device will be dropped, but the port remains active.

Answer

The switch will allow the third device and remove the oldest MAC.

Question 4

Which protocol is used to provide dynamic, automatic configuration of VLANs across a domain of switches?

Accepted Answer

VTP. VLAN Trunking Protocol (VTP) enables a centralized management of VLAN configurations across a switched network. By creating, deleting, or modifying VLANs on a server switch, those changes are propagated automatically to all client switches in the domain. Understanding VTP is essential for minimizing configuration errors and maintaining consistent VLAN databases in large-scale environments, though modern networks often prefer manual management for improved security control.

Answer

STP

Answer

CDP

Answer

OSPF

Question 5

Which THREE of the following are characteristics of the Cisco IOS CLI environment that facilitate efficient network administration?

Accepted Answer

Context-sensitive help using the question mark symbol.. The Cisco IOS CLI provides robust tools for configuration and troubleshooting, including contextual help, command completion, and error feedback. These features are designed to speed up the work of network engineers by reducing the need for documentation lookups and minimizing syntax errors. Mastering these CLI features is essential for any technician tasked with managing Cisco infrastructure, as it improves accuracy and efficiency during high-pressure maintenance windows.

Answer

Automatic translation of all commands into GUI equivalents.

Answer

Direct integration with external cloud storage for backups.

Question 6

A switch is experiencing high levels of broadcast traffic. Which technology can be used to divide the switch into smaller, independent broadcast domains?

Accepted Answer

VLANs. VLANs logically partition a single physical switch into multiple separate Layer 2 broadcast domains, so broadcast frames from one VLAN are not flooded to ports in another VLAN. This directly reduces the size of each broadcast domain and the overall broadcast traffic per segment. VLANs are defined in IEEE 802.1Q and are the standard method for broadcast domain segmentation on switches.

Answer

VTP (VLAN Trunking Protocol)

Answer

Port Security

Answer

STP (Spanning Tree Protocol)

Question 7

What is the primary function of the 'show running-config' command on a Cisco switch?

Accepted Answer

To view the active configuration stored in RAM.. The 'show running-config' command displays the current active configuration stored in RAM. This command is vital for verification, as it allows administrators to see exactly how the device is configured in real-time. Knowing how to interpret this output is essential for troubleshooting, as it reveals the current status of interfaces, security settings, and routing protocols before they are saved to the permanent startup configuration.

Answer

To save the current configuration to NVRAM.

Answer

To clear all existing configurations on the device.

Answer

To view the hardware version and serial number.

Question 8

Which component of the Cisco network architecture is specifically designed to provide high-speed switching and fast transport between different parts of the network?

Accepted Answer

Core Layer. The Core Layer of the Cisco network architecture is designed for high-speed switching and fast transport between different parts of the network. It acts as the backbone, connecting distribution layer devices and providing a high-capacity, low-latency path for data. The core should be highly resilient and avoid processing-intensive tasks like access control lists.

Answer

Access Layer

Answer

Distribution Layer

Answer

Edge Layer

Question 9

What is the primary function of the Spanning Tree Protocol (STP) in a network with redundant links?

Accepted Answer

To prevent Layer 2 loops.. STP's primary function is to prevent Layer 2 loops by creating a loop-free logical topology. In a network with redundant links, STP elects a root bridge, determines root ports and designated ports, and blocks redundant ports to eliminate loops. This prevents broadcast storms and MAC address table instability that would otherwise occur due to frames circulating indefinitely.

Answer

To increase the total bandwidth of multiple links.

Answer

To assign IP addresses to switches.

Answer

To route traffic between different VLANs.

Question 10

Refer to the exhibit. What can be determined about the status of interface FastEthernet 0/1?

Accepted Answer

The interface is working correctly at the physical and data link layers.. The output shows the interface is administratively up and the line protocol is up, indicating a functional physical link with an active Layer 2/3 configuration. This is the ideal state for a production interface. Being able to interpret 'show ip interface brief' is a mandatory skill for quickly diagnosing whether issues are physical, configuration-related, or protocol-based in enterprise network troubleshooting scenarios.

Answer

The interface is disabled and needs to be enabled.

Answer

The interface has no IP address assigned to it.

Answer

There is a physical layer problem preventing connectivity.

Question 11

A technician connects a new laptop to a Cisco Catalyst switch. The switch receives a frame destined for a MAC address that is not currently present in its MAC address table. What action will the switch take to ensure the frame reaches its intended destination?

Accepted Answer

The switch floods the frame out of all ports within the same VLAN, except for the port where the frame was received.. Switches use the MAC address table to make intelligent forwarding decisions. When a destination MAC address is missing from the table, the switch performs an unknown unicast flood. This mechanism ensures that the frame is delivered to the target device wherever it might be located within the broadcast domain. Understanding this fundamental behavior is critical for troubleshooting connectivity issues and analyzing traffic flow within a local area network environment.

Answer

The switch drops the frame immediately and sends an ICMP Destination Unreachable message to the source.

Answer

The switch forwards the frame to the default gateway to be resolved by a Layer 3 routing process.

Answer

The switch buffers the frame and generates an ARP request to determine the correct exit port for the destination MAC.

Question 12

A network technician is configuring a new Cisco switch port for a server that must support both voice and data traffic on separate VLANs. The server's network interface card is VLAN-aware and will tag its own frames. The technician wants to ensure the switch port can carry traffic for multiple VLANs. Which type of switch port configuration should the technician apply?

Accepted Answer

Trunk port. A trunk port is designed to carry traffic for multiple VLANs using 802.1Q tagging. Because the server's NIC is VLAN-aware and will tag frames, the switch port must be configured as a trunk to accept and forward those tagged frames. Access ports support only a single VLAN, and routed ports operate at Layer 3 without VLAN tagging.

Answer

Native VLAN port

Answer

Access port

Answer

Routed port

Question 13

A network technician is configuring a new Cisco switch and needs to assign an IP address to the management VLAN interface so the switch can be reached remotely via SSH. The switch currently has no VLAN interfaces configured. Which command must the technician use to create the management interface and enter interface configuration mode?

Accepted Answer

interface vlan 1. To assign a management IP to a Cisco switch, an SVI must be configured. The command interface vlan 1 creates the SVI for VLAN 1 and enters interface configuration mode, where an IP address can be assigned. Physical ports are Layer 2 and cannot hold IP addresses, and the vlan command only creates VLANs, not interfaces.

Answer

vlan 1

Answer

interface fastethernet 0/1

Answer

ip address 192.168.1.10 255.255.255.0

Question 14

A network administrator is setting up a small office network with a Cisco router and several switches. The administrator wants to ensure that devices on the local network can communicate with each other and access the internet. Which IP address configuration parameter must be set on each device to allow communication with remote networks?

Accepted Answer

Default gateway. The default gateway is the router's IP address on the local subnet that devices use to forward packets destined for remote networks. Without it, a device can only communicate locally. The subnet mask helps identify local versus remote destinations, but the default gateway provides the actual path to those remote networks.

Answer

MAC address

Answer

DNS server

Answer

Subnet mask

Question 15

A network technician connects a new Cisco Catalyst switch to an existing production switch using a copper straight-through cable. The link lights on both ends remain off, and the technician confirms the cable is functional. The technician then replaces the cable with a crossover cable, and the link comes up. What is the most likely reason the straight-through cable failed to establish a link?

Accepted Answer

The new switch does not support Auto-MDIX, and both devices use the same pinout for transmit and receive pairs.. Two switches connected with a straight-through cable without Auto-MDIX will not establish a link because transmit and receive pairs are not crossed. A crossover cable swaps the pairs, allowing the link to come up. The scenario confirms the cable itself is functional, so the issue is the pinout mismatch between similar devices.

Answer

The straight-through cable is wired to T568A on one end and T568B on the other.

Answer

The switch port on the existing production switch is configured as a trunk port.

Answer

The existing production switch port is shut down administratively.