100-150 Practice Test 18 — 15 Questions

Question 1

A network administrator needs to prevent unauthorized devices from connecting to switch ports. Which feature provides the most effective Layer 2 security by verifying the MAC address of the connected device against a database?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Port Security. Port Security allows administrators to secure access to ports by locking a specific MAC address to that port. This prevents unauthorized devices from gaining network access. In a Cisco enterprise environment, this is a fundamental defense-in-depth measure against unauthorized physical access. By restricting the number and identity of MAC addresses, the network remains resilient against simple spoofing or unauthorized hardware insertions, ensuring that only trusted endpoints communicate through the designated access layer infrastructure.

Answer

DHCP Snooping

Answer

BPDU Guard

Answer

Dynamic ARP Inspection

Question 2

Which of the following is a Class C IP address?

Accepted Answer

192.168.1.1. Class C IP addresses have a first octet in the range 192–223, and 192.168.1.1 falls within that range. Class C addresses use a default /24 subnet mask (255.255.255.0) and were historically assigned to small networks. This makes 192.168.1.1 the correct answer.

Answer

10.5.5.5

Answer

172.16.1.1

Answer

224.1.1.1

Question 3

A technician is troubleshooting a workstation that cannot connect to the network. The workstation's network interface card (NIC) shows a link light, but no data is being transmitted. The cable is a straight-through Cat 5e patch cord. Which tool should the technician use to verify the cable's pinout and detect any wiring faults?

Accepted Answer

Cable tester. A cable tester is specifically designed to verify the integrity and pinout of network cables. It can detect common wiring faults such as opens, shorts, and crossed pairs that might allow link but prevent data flow. The other tools serve different purposes: tone generators trace cables, loopback plugs test ports, and multimeters check basic electrical properties. Thus, a cable tester is the correct tool for this scenario.

Answer

Loopback plug

Answer

Multimeter

Answer

Tone generator and probe

Question 4

Which protocol is primarily used for the delivery of real-time voice and video media streams across a network?

Accepted Answer

RTP (Real-time Transport Protocol). The Real-time Transport Protocol (RTP) is the standard for delivering audio and video over IP networks. Because it operates over UDP, it provides the low-overhead delivery mechanism necessary for real-time applications. Understanding RTP is foundational for network troubleshooting, as most packet analysis of voice media will involve inspecting RTP streams to detect drops, out-of-order delivery, or timestamp mismatches that impact audio clarity.

Answer

SIP (Session Initiation Protocol)

Answer

TCP (Transmission Control Protocol)

Answer

DNS (Domain Name System)

Question 5

A network technician is tasked with connecting two buildings located 1.5 kilometers apart. Which media type should be selected to ensure reliable data transmission over this distance without the need for repeaters?

Accepted Answer

Single-mode Fiber (OS2). Single-mode fiber is the only standard media type capable of transmitting data over distances exceeding several kilometers without significant signal degradation. Unlike multi-mode fiber, which is limited by modal dispersion over long runs, single-mode fiber uses a narrow glass core and laser light to maintain signal integrity over many miles, making it the primary choice for campus backbones.

Answer

Multi-mode Fiber (OM4)

Answer

Category 6a UTP

Answer

Shielded Twisted Pair (STP)

Question 6

A network technician is installing network drops in a factory with heavy machinery that generates significant electromagnetic interference (EMI). Which cable type would best protect the data from corruption?

Accepted Answer

STP (Shielded Twisted Pair). Electromagnetic interference can severely degrade network performance by introducing noise into copper cables. In environments like factories where high-voltage equipment is present, standard unshielded cabling is insufficient. Technicians must select cables with extra shielding to block external noise and maintain the integrity of the data signals.

Answer

UTP (Unshielded Twisted Pair)

Answer

Plenum-rated UTP

Answer

Category 5e Patch Cable

Question 7

A network administrator is implementing IPv6 in a corporate environment. Which TWO address types are commonly used to facilitate local link communication and global internet access respectively?

Accepted Answer

Link-Local Address (FE80::/10). Option A, the Link-Local Address (FE80::/10), is correct because every IPv6-enabled interface automatically configures a link-local address within the FE80::/10 prefix, which is used for communication on the local segment only (neighbor discovery, router solicitation, and next-hop resolution) and is never routed beyond the link. Option C, the Global Unicast Address (2000::/3), is correct because this is the range from which globally routable IPv6 addresses are allocated, allowing hosts to communicate across the public internet. Option B, the Unique Local Address (FC00::/7), is not correct here because it is designed for private, non-internet-routed communication within an organization, not global internet access. Option D, the Multicast Address (FF00::/8), is not correct because it identifies groups of interfaces for one-to-many delivery rather than providing local link or global unicast communication. Option E, the Loopback Address (::1/128), is not correct because it is used only for a node to send traffic to itself, not for link or internet communication.

Answer

Unique Local Address (FC00::/7)

Answer

Multicast Address (FF00::/8)

Answer

Loopback Address (::1/128)

Question 8

A startup wants to host a custom application in the cloud without managing the underlying operating system or hardware. Which THREE cloud service models or characteristics are relevant to this requirement?

Accepted Answer

PaaS. Cloud computing offers various service models depending on the level of management required by the customer. Platform as a Service (PaaS) is ideal for developers who want to focus on code rather than infrastructure. Understanding these models helps organizations choose the right balance between control and operational overhead for their specific workloads.

Answer

SaaS

Answer

IaaS

Question 9

A network engineer is analyzing a packet capture and notices that a TCP segment has the SYN flag set and the ACK flag set. The source port is 80 and the destination port is 49152. What does this indicate about the TCP connection?

Accepted Answer

It is the second step of the three-way handshake, where the server acknowledges the client's SYN and sends its own SYN.. A TCP segment with both SYN and ACK flags set is a SYN-ACK, which is the second step of the three-way handshake. The server sends it in response to the client's initial SYN. The source port 80 identifies the server, and the destination port 49152 is the client's ephemeral port, confirming the direction.

Answer

It is the third step of the three-way handshake, where the client acknowledges the server's SYN.

Answer

It is the first step of the three-way handshake, where a client initiates a connection to a server.

Answer

It is a simultaneous open, where both hosts send SYN segments at the same time.

Question 10

An employee receives an email that appears to be from the company's IT department, requesting their login credentials to perform an urgent system update. What type of social engineering attack does this represent?

Accepted Answer

Phishing. Social engineering relies on psychological manipulation to trick individuals into divulging confidential information or performing actions that compromise security. Phishing is the most common form of this attack, often delivered via email. Training employees to recognize these deceptive tactics is a critical part of a modern security awareness program.

Answer

Tailgating

Answer

Shoulder Surfing

Answer

Man-in-the-Middle

Question 11

Which endpoint media issue is most likely caused by the use of asymmetric paths in a bi-directional voice call?

Accepted Answer

Increased jitter due to varying path delays in each direction.. Asymmetric routing occurs when packets follow different paths to and from an endpoint. This often causes jitter and latency variations that exceed the capabilities of the endpoint's jitter buffer. Identifying this issue is crucial because it is a network-layer problem that cannot be solved by upgrading phone firmware or codecs, requiring instead a review of the routing protocol design and load balancing configurations.

Answer

One-way audio where the caller cannot hear the callee.

Answer

Ghost calls that register spontaneously on the gateway.

Answer

Registration failure between the endpoint and the Call Agent.

Question 12

What is the primary function of a loopback interface in troubleshooting network devices?

Accepted Answer

To provide a stable interface for management and testing.. A loopback interface is a logical, virtual interface that is always 'up' as long as the router is running. It is primarily used for management, testing, and as a stable source IP for routing protocols like OSPF and BGP. Because it is never dependent on physical cable status, it provides a reliable point for testing connectivity and management access regardless of physical link failures.

Answer

To act as a physical bridge between two VLANs.

Answer

To increase the total bandwidth of the router.

Answer

To provide power over Ethernet to connected devices.

Question 13

A network administrator is configuring a new Cisco switch. The administrator wants to ensure that management traffic for SSH and SNMP is separated from user data and that only the management VLAN can reach the switch's management IP address. Which action should the administrator take?

Accepted Answer

Create a dedicated management VLAN, assign the switch's management IP address to that VLAN, and place only management-connected ports in it.. Best practice is to create a dedicated management VLAN, assign the switch's management IP address to its switched virtual interface, and connect only management devices to ports in that VLAN. This keeps SSH and SNMP traffic isolated from user data and reduces the attack surface on the management plane.

Answer

Configure a trunk port to carry all VLANs, including VLAN 1, and set the native VLAN to the management VLAN on all access ports.

Answer

Disable VLAN 1 and assign the management IP address to the default VLAN 100, which is automatically created for management purposes.

Answer

Assign the management IP address to VLAN 1 and place all user ports in VLAN 1 as well, then apply an ACL to the management interface.

Question 14

What is the decimal equivalent of the subnet mask 255.255.255.224?

Accepted Answer

/27. The subnet mask 255.255.255.224 corresponds to a /27 CIDR notation. The first three octets are all ones, and the last octet consists of three ones followed by five zeros (11100000), which equals 224 in decimal. Identifying CIDR masks from decimal notation is a core competency for Cisco technicians, as it is required for rapid network design and troubleshooting in real-world infrastructure environments.

Answer

/25

Answer

/26

Answer

/28

Question 15

What is the primary function of a firewall when placed at the edge of a network?

Accepted Answer

To filter traffic based on security policies. A firewall acts as the security boundary between an internal trusted network and an untrusted external network like the internet. By enforcing security policies based on traffic inspection, it prevents unauthorized access and limits potential threats. This is a crucial component of any security strategy, as it provides a centralized point to filter traffic, monitor for suspicious patterns, and maintain the integrity of the internal network infrastructure.

Answer

To increase the network bandwidth

Answer

To provide automatic physical layer redundancy

Answer

To automatically patch all internal servers