100-150 Practice Exam 4 — 20 Questions

Question 1

Which protocol operates at the Application layer of the TCP/IP model and is used to resolve hostnames into IP addresses?

Accepted Answer

DNS. DNS (Domain Name System) operates at the Application layer of the TCP/IP model and is responsible for resolving human-readable hostnames (like www.example.com) into IP addresses. It uses UDP port 53 for standard queries and TCP port 53 for zone transfers and large responses.

Answer

DHCP

Answer

ARP

Answer

HTTP

Question 2

A network administrator needs to ensure that data remains confidential during transit across an untrusted network. Which protocol implementation best addresses this requirement?

Accepted Answer

SSH. SSH (Secure Shell) provides encrypted, authenticated communication over untrusted networks, typically on TCP port 22, using strong cryptographic algorithms to protect data in transit. It replaces insecure remote-access protocols like Telnet by encrypting the entire session, ensuring confidentiality and integrity. This directly satisfies the requirement that data remain confidential during transit.

Answer

Telnet

Answer

HTTP

Answer

SNMPv1

Question 3

Which TWO of the following statements regarding IPv6 address representation are accurate?

Accepted Answer

Leading zeros in a 16-bit field can be omitted.. Option B is correct because RFC 4291 allows leading zeros within any 16-bit hexadecimal field (hextet) to be dropped, so 0db8 can be written as db8. Option D is correct because the double-colon (::) is the compression notation that stands in for one or more consecutive 16-bit groups that are all zeros, and it may appear only once in an address. Option A is wrong because :: can be used only a single time per address; using it twice would make the number of omitted zero groups ambiguous. Option C is wrong because IPv6 addresses are commonly written in compressed form, not always as a full 32-character hexadecimal string. Option E is wrong because only leading zeros may be omitted; trailing zeros are significant and must be retained.

Answer

The double-colon (::) can be used multiple times in a single IPv6 address to shorten it.

Answer

An IPv6 address must always be written in full 32-character hexadecimal format.

Answer

Trailing zeros in a 16-bit field can be omitted.

Question 4

An administrator needs to subnet the 192.168.10.0/24 network into subnets that can support at least 25 hosts each. Which subnet mask provides the maximum number of subnets while meeting the host requirement?

Accepted Answer

255.255.255.224. To support at least 25 hosts, the subnet must have at least 5 host bits (2^5 - 2 = 30 usable hosts). A /27 mask (255.255.255.224) leaves 5 host bits, providing 30 usable addresses per subnet and yielding 8 subnets from a /24. This maximizes subnet count while still meeting the 25-host requirement.

Answer

255.255.255.248

Answer

255.255.255.240

Answer

255.255.255.192

Question 5

A technician is installing a new set of outdoor wireless access points. Which TWO factors are most likely to cause signal attenuation or interference for these endpoints?

Accepted Answer

Thick concrete walls and metal structures. Option A is correct because thick concrete walls and metal structures are dense physical obstructions that absorb, reflect, and scatter RF energy, causing significant signal attenuation, especially at higher frequencies like 5 GHz and 6 GHz. Option C is correct because 2.4 GHz cordless phones and microwave ovens operate in or near the 2.4 GHz ISM band and emit RF energy that overlaps with WLAN channels, producing co-channel and adjacent-channel interference. Option B is not a factor because Category 6a cabling is a wired Ethernet medium for the backhaul and does not radiate or attenuate wireless signals in a way that affects RF propagation. Option D is not a factor because PoE+ (802.3at) is simply a power-delivery standard over Ethernet and does not cause RF attenuation or interference. Option E is not a factor because an LC-to-LC fiber patch cord carries optical signals for wired backhaul and is immune to RF interference and does not affect wireless signal quality.

Answer

The use of Category 6a cabling for the backhaul

Answer

Configuring the access point for PoE+ (802.3at)

Answer

Using an LC-to-LC fiber patch cord

Question 6

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 7

Which tool is best suited for identifying a slow network segment caused by excessive broadcast traffic?

Accepted Answer

Protocol analyzer.. Broadcast storms or high volumes of traffic can severely degrade network performance. A protocol analyzer, or network sniffer, allows a technician to capture packets and examine the distribution of traffic types. By looking at the percentage of broadcast traffic compared to unicast traffic, one can identify if a specific segment is being overwhelmed by broadcast frames, which is critical for maintaining network latency and stability.

Answer

Cisco DNA Center.

Answer

SNMP Manager.

Answer

TDR cable tester.

Question 8

A network technician is troubleshooting a PC that cannot access internal network resources. Which TWO steps are recommended to verify if the PC is receiving a valid IP address?

Accepted Answer

Run ipconfig on the workstation.. Verifying the IP configuration is essential when network access fails. Using 'ipconfig' allows the technician to see if the PC has a valid address, subnet mask, and gateway. Checking the DHCP server configuration ensures that the scope is not exhausted and that the client is actually communicating with the server. These two steps confirm if the layer 3 addressing is correct before moving on to more complex layer 2 or routing issues.

Answer

Check the switch interface status.

Answer

Perform a traceroute to the local gateway.

Answer

Reset the switch configuration.

Question 9

A network engineer is troubleshooting a potential DHCP issue. Which THREE components are provided to a client during a successful DHCP 'Acknowledgment' (ACK) message? (Choose three.)

Accepted Answer

IP address for the client.. The DHCP ACK is the final step in the DORA process where the server confirms the lease of an IP address. Understanding the specific parameters delivered in this message is crucial for diagnosing configuration errors that affect host connectivity, name resolution, and the ability of devices to reach resources outside their local network segment.

Answer

The MAC address of the DHCP server.

Answer

The SSH private key for the management console.

Question 10

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 11

An administrator is configuring Power over Ethernet on an enterprise access switch to power IP security cameras requiring up to 25.5 watts of power each. Which IEEE standard must the switch ports support?

Accepted Answer

IEEE 802.3at delivering up to 30 watts of direct current power per individual port interface.. IEEE 802.3at (PoE+) delivers up to 30 watts of DC power per port, which comfortably exceeds the 25.5-watt requirement of the IP cameras. This standard uses two pairs of Cat5e or better cabling to provide the higher power budget while maintaining backward compatibility with 802.3af devices. The switch port must support 802.3at to guarantee sufficient power for each camera without overloading the power budget.

Answer

IEEE 802.3af delivering a maximum of 15.4 watts of direct current power per individual port interface.

Answer

IEEE 802.3bt Type 3 delivering up to 60 watts of power across all four wire pairs within the structured copper cable.

Answer

IEEE 802.3ab defining Gigabit Ethernet physical layer transmission parameters over copper infrastructure.

Question 12

A technician is installing a new 10GBASE-T network card in a server and needs to select the appropriate copper cabling. Which cable category is the minimum requirement to support 10 Gbps speeds at a distance of 100 meters?

Accepted Answer

Category 6a. 10GBASE-T over copper requires Category 6a (augmented Cat 6) to reliably achieve 10 Gbps at the full 100-meter channel length. Cat 6a is specified to 500 MHz and is designed to handle the higher alien crosstalk and signal-to-noise requirements of 10GBASE-T. Cat 6 can only support 10GBASE-T up to about 55 meters, not 100 meters.

Answer

Category 5e

Answer

Category 6

Answer

Category 3

Question 13

A network engineer is migrating a network to IPv6 to solve address exhaustion. Which feature of IPv6 eliminates the need for broadcasting to discover MAC addresses on a local link?

Accepted Answer

NDP. IPv6 Neighbor Discovery Protocol (NDP) replaces ARP and uses ICMPv6 messages (Neighbor Solicitation and Neighbor Advertisement) to resolve IPv6 addresses to MAC addresses on a local link. NDP eliminates the need for broadcasting because it uses multicast addresses (solicited-node multicast) to efficiently discover neighbors, making it the correct answer.

Answer

NAT

Answer

ARP

Answer

DHCPv6

Question 14

A network administrator needs to connect a workstation to a Cisco switch. Which cabling standard and medium should be utilized to ensure full-duplex communication while preventing collision domains?

Accepted Answer

Category 6 twisted-pair cable with full-duplex settings. Category 6 twisted-pair cable with full-duplex settings is the correct combination because modern Ethernet switches support full-duplex on twisted-pair, which eliminates collisions by providing separate transmit and receive paths on different wire pairs. Cat 6 supports gigabit speeds at 100 meters and is the appropriate medium for a workstation-to-switch connection. Full-duplex operation removes the collision domain entirely on that link.

Answer

Coaxial cable with half-duplex settings

Answer

Fiber optic cable with half-duplex settings

Answer

Category 3 twisted-pair cable with full-duplex settings

Question 15

A technician can successfully ping local servers on the same 192.168.10.0/24 subnet but cannot reach any resources on a different VLAN or the Internet. The technician verifies the local IP address and subnet mask are correct. Which component is the most likely source of the connectivity failure?

Accepted Answer

Misconfigured default gateway. Successful communication within a local subnet proves that the Network Interface Card and local switching are functional. However, the inability to reach remote networks typically indicates a configuration error regarding the default gateway. Technicians must verify that the gateway address resides on the local subnet and that the router is actively forwarding traffic for that specific VLAN.

Answer

Incorrect DNS server

Answer

Duplicate IP address

Answer

Faulty Cat6 cabling

Question 16

A junior technician is organizing a box of fiber optic patch cords. Which TWO connector types are commonly used to terminate modern fiber optic media? (Choose TWO.)

Accepted Answer

LC (Lucent Connector). Identifying physical connectors is a fundamental skill for network support technicians working with fiber infrastructure. LC and SC connectors are the industry standards for most enterprise networking equipment. Knowledge of these connectors prevents damage to SFP modules and patch panels that may occur if a technician attempts to force an incompatible physical connection.

Answer

RJ-45

Answer

BNC

Answer

F-type

Question 17

Refer to the exhibit. A company applies this JSON security policy to its edge firewall. What is the primary standard or concept being enforced by this configuration?

Accepted Answer

Confidentiality. This policy demonstrates the enforcement of secure web communication standards. By denying traffic on port 80 (HTTP) and allowing traffic on port 443 (HTTPS), the organization ensures that all web data is encrypted during transit. This is a fundamental security practice to protect sensitive information from being intercepted by unauthorized parties.

Answer

Data Integrity

Answer

Availability

Answer

Physical Security

Question 18

Which TWO of the following statements regarding IPv4 address types are true?

Accepted Answer

Public IP addresses are globally routable across the internet.. Understanding the distinction between private, public, and special-use IPv4 addresses is critical for network security and traffic routing. Private addresses allow internal segmentation without internet visibility, while special addresses like the loopback range are essential for local service testing. Mastering these types prevents common errors like NAT misconfiguration or routing traffic into non-existent or internal-only address blocks across the network infrastructure.

Answer

Private IP addresses can be routed directly across the public internet.

Answer

The 127.0.0.0/8 range is used for private internal communication.

Answer

All IPv4 addresses are assigned automatically by the ISP.

Question 19

Refer to the exhibit. A technician is troubleshooting a connection between a Cisco switch and a server. Based on the output, what is the most likely cause of the 'line protocol is down' status?

Accepted Answer

A duplex or speed mismatch exists.. In Cisco IOS, the status 'up/down' typically indicates a Layer 2 framing or configuration mismatch rather than a physical break. While the physical layer is active, the line protocol fails due to issues like duplex mismatches, encapsulation errors, or keepalive failures. Identifying this distinction allows technicians to focus on software configuration rather than replacing hardware.

Answer

The physical cable is disconnected.

Answer

The switch port has been administratively disabled.

Answer

The MAC address on the server is incorrect.

Question 20

Which primary benefit does the implementation of VLANs provide to a corporate network infrastructure?

Accepted Answer

Reduction of broadcast domain size. VLANs divide a single physical switch into multiple logical broadcast domains. This segmentation reduces the size of broadcast domains, which minimizes unnecessary traffic processing on end devices and improves overall network stability. By grouping devices logically rather than physically, administrators gain greater control over resource access and improve security by isolating traffic between different departments or functional roles.

Answer

Increased physical cabling requirements

Answer

Automatic encryption of all traffic

Answer

Elimination of the need for routers