100-150 Practice Test 4 — 10 Questions

Question 1

A network designer is choosing between SFP and SFP+ transceivers for a new switch deployment. Which TWO statements correctly describe the differences and compatibility between these media modules?

Accepted Answer

SFP modules typically support speeds up to 1 Gbps. Option A is correct because SFP (Small Form-factor Pluggable) transceivers are specified for Gigabit Ethernet and lower rates, typically up to 1 Gbps, making them the standard choice for 1000BASE-X/SX/LX/T connections. Option B is correct because SFP+ is the enhanced variant standardized for 10 Gbps Ethernet (10GBASE-SR/LR/ER and DAC), which is its primary design purpose. Option C is wrong because SFP+ in an SFP slot is not guaranteed; the slot must explicitly support 10 Gbps and often requires the same form factor with matching electrical characteristics, so it will not 'always' work. Option D is wrong because SFP modules support fiber connectors such as LC (and sometimes SC), plus copper variants like 1000BASE-T use RJ-45, so RJ-45 is not exclusive. Option E is wrong because SFP+ modules exist for both single-mode and multimode fiber (e.g., 10GBASE-SR for MMF, 10GBASE-LR for SMF), so single-mode-only is inaccurate.

Answer

An SFP+ module will always work in a standard SFP slot

Answer

SFP modules use RJ-45 connectors exclusively

Answer

SFP+ modules are only compatible with single-mode fiber

Question 2

Which of the following is the correct representation of the IPv6 address 2001:0DB8:0000:0000:0008:0800:200C:417A in compressed format?

Accepted Answer

2001:DB8::8:800:200C:417A. The correct compressed format is 2001:DB8::8:800:200C:417A. IPv6 compression rules (RFC 5952) allow leading zeros in each group to be omitted and a single contiguous sequence of all-zero groups to be replaced with '::'. Here, the two consecutive zero groups (0000:0000) are replaced by '::', and leading zeros in other groups are dropped (0DB8→DB8, 0008→8, 0800→800).

Answer

2001:DB8:0:0:8:800:200C:417A

Answer

2001:DB8::0000::8:800:200C:417A

Answer

2001:DB8:0000:0000:8:800:200C:417A

Question 3

What is the directed broadcast address for the subnet in which the host 172.16.50.131/29 resides?

Accepted Answer

172.16.50.135. For 172.16.50.131/29, the subnet mask is 255.255.255.248, meaning each subnet has 8 addresses (2^3). The subnet containing .131 starts at .128 (network address) and ends at .135 (broadcast address). The directed broadcast address is the last address in the subnet, which is 172.16.50.135.

Answer

172.16.50.159

Answer

172.16.50.255

Answer

172.16.50.133

Question 4

A technician needs to identify which endpoint is connected to a specific switch port. Which command should be used to see the Layer 2 address of the connected device and the port it is associated with?

Accepted Answer

show mac address-table. The show mac address-table command displays the switch's MAC address table, which maps MAC addresses to switch ports and VLANs. This allows a technician to identify which endpoint (by its Layer 2 MAC address) is connected to a specific port. It is the standard Cisco IOS command for Layer 2 endpoint-to-port mapping.

Answer

show ip route

Answer

show interfaces status

Answer

show running-config

Question 5

A network technician is configuring a point-to-point serial link between two Cisco routers. To conserve address space, the engineer wants the smallest possible subnet that still provides two usable host addresses. Which subnet mask should be applied to the serial interfaces?

Accepted Answer

255.255.255.252. A point-to-point serial link requires only two host addresses, one for each router interface. The /30 mask 255.255.255.252 provides exactly four addresses, of which two are usable hosts, making it the smallest conventional subnet for this purpose. Larger masks waste addresses, and while /31 is an option in some modern implementations, the /30 remains the standard expected configuration for conserving address space on WAN links.

Answer

255.255.255.254

Answer

255.255.255.128

Answer

255.255.255.248

Question 6

A technician needs to connect a laptop to a Cisco router's console port to perform initial configuration. Which cable should be used for this task?

Accepted Answer

Rollover cable. A rollover cable (also called a console cable) is specifically wired to connect a computer's serial port (via a DB-9 or USB adapter) to a Cisco router's console port (RJ-45). The pinout is reversed end-to-end, which is why it is called a rollover cable. It is the standard cable for out-of-band initial configuration and password recovery.

Answer

Straight-through Ethernet cable

Answer

Crossover Ethernet cable

Answer

Single-mode fiber patch cord

Question 7

Users on a floor of an office building report that file transfers to a server are slow and sometimes stall. The technician suspects a duplex mismatch on the switch port connecting the server. Which TWO symptoms or outputs would confirm a duplex mismatch on that link? (Choose two.)

Accepted Answer

The switch interface shows a high number of FCS and CRC errors on received frames.. A duplex mismatch produces collisions on the half-duplex side while the full-duplex side keeps transmitting, corrupting frames in flight. The two clearest confirmations are late collisions counted on the half-duplex interface and CRC or FCS errors counted on received frames. Both counters rise steadily under load, and throughput drops because corrupted frames must be retransmitted by upper-layer protocols.

Answer

The switch logs show the port entering the err-disabled state repeatedly.

Answer

The switch port shows the line protocol as down while the physical link remains up.

Answer

The server's NIC reports a negotiated speed of 1000 Mb/s and full duplex.

Question 8

A company wants to ensure that even if an attacker steals a user's password, the attacker cannot log in without a second factor. Which authentication approach best meets this requirement?

Accepted Answer

Combining a password with a one-time code from an authenticator app. Multi-factor authentication requires two different categories of proof, such as something the user knows (password) and something the user has (an authenticator app generating one-time codes). A stolen password alone is useless without the second factor. Password complexity, lockout, and expiration all strengthen a single factor but do not prevent misuse of a stolen password.

Answer

Requiring a longer and more complex password

Answer

Locking accounts after three failed login attempts

Answer

Enforcing a password expiration policy every 30 days

Question 9

Which TWO characteristics distinguish the User Datagram Protocol (UDP) from the Transmission Control Protocol (TCP)?

Accepted Answer

UDP provides connectionless communication without a handshake.. The choice between TCP and UDP is a fundamental architectural decision based on the needs of the application. TCP provides reliability and flow control at the cost of overhead, while UDP prioritizes speed and efficiency. Understanding these differences allows network professionals to troubleshoot performance issues and optimize traffic for different types of data, such as streaming or file transfers.

Answer

UDP uses sequence numbers to reassemble data in the correct order.

Answer

UDP operates at the Network Layer of the OSI model.

Answer

UDP includes a three-way handshake to ensure delivery.

Question 10

Which Cisco feature is used to prevent Man-in-the-Middle attacks that rely on corrupting the ARP cache of connected hosts?

Accepted Answer

Dynamic ARP Inspection. ARP spoofing allows attackers to associate their MAC address with the IP address of a default gateway, effectively intercepting traffic. Dynamic ARP Inspection (DAI) uses the DHCP snooping database to validate ARP packets, ensuring that only legitimate mappings are allowed. This is a critical security feature in modern switches to prevent internal traffic interception, ensuring data privacy and integrity between hosts on the same Layer 2 domain.

Answer

DHCP Snooping

Answer

Port Security

Answer

IP Source Guard