N10-009 Practice Test 9 — 10 Questions

Question 1

A user reports that they can connect to the corporate Wi-Fi network but cannot access any network resources including the intranet and internet. The IP configuration shows an IP address of 169.254.25.100 with a subnet mask of 255.255.0.0. What is the most likely cause?

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

Accepted Answer

The DHCP server is unavailable or the request is not reaching it. The IP address 169.254.25.100 with a subnet mask of 255.255.0.0 is an Automatic Private IP Addressing (APIPA) address, which is assigned by the operating system when a DHCP server is unavailable or the DHCP request fails. Since the user can connect to Wi-Fi but cannot access any network resources, the most likely cause is that the DHCP server is not responding or the DHCP discover/offer/request/ack sequence is failing, leaving the device with a link-local address that cannot route to the corporate network or internet.

Answer

The DNS server is not responding

Answer

The subnet mask is incorrect

Answer

The switch port has port security enabled that has blocked the device

Question 2

A network technician is explaining the difference between TCP and UDP to a junior technician. Which of the following correctly identifies a characteristic of TCP but NOT of UDP?

Accepted Answer

It uses a three-way handshake to establish a connection before data transfer.. TCP is a connection-oriented protocol that uses a three-way handshake (SYN, SYN-ACK, ACK) to establish a reliable connection before any data is transmitted, ensuring ordered delivery and error recovery. UDP, in contrast, is connectionless and sends datagrams without any prior setup, making the three-way handshake a defining characteristic of TCP only.

Answer

It provides connectionless communication with minimal overhead.

Answer

It supports multicast and broadcast transmissions.

Answer

It is commonly used for real-time applications like VoIP and video streaming.

Question 3

A security analyst notices that a user's workstation is sending encrypted DNS queries to an external IP address over TCP port 853. This traffic is being used to establish a covert communication channel to bypass the company's security controls. Which technique is being employed?

Accepted Answer

DNS tunneling. DNS tunneling is the correct answer because the analyst observed encrypted DNS queries over TCP port 853 (DNS over TLS) being used to establish a covert communication channel. This technique encapsulates non-DNS data (e.g., command-and-control traffic) within DNS query and response packets, allowing the attacker to bypass security controls by hiding malicious traffic inside legitimate DNS traffic.

Answer

DNS poisoning

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DNS amplification

Answer

DNS zone transfer

Question 4

A network administrator wants to collect logs from multiple routers and switches to a central server for analysis. Which protocol should be configured on the devices to send logs to the server?

Accepted Answer

Syslog. Syslog (RFC 5424) is the standard protocol for sending event messages (logs) from network devices like routers and switches to a central log server. It uses UDP port 514 by default (or TCP 6514 for reliable delivery) and allows administrators to collect, store, and analyze system messages from multiple devices in one location.

Answer

SNMP

Answer

NetFlow

Answer

TFTP

Question 5

A network engineer needs to install 15 wireless access points that each require 25W of power. The available switch provides PoE+ (802.3at) with a total power budget of 740W. The engineer also needs to connect 10 IP cameras that each require 12W. Which of the following should the engineer verify before proceeding with the installation?

Accepted Answer

The total power consumption of all devices does not exceed the switch's power budget.. The total power required is 15 APs × 25W + 10 cameras × 12W = 375W + 120W = 495W, which is well below the switch's 740W PoE+ budget. However, the engineer must verify that the cumulative power draw does not exceed the budget, as exceeding it would cause some ports to be denied power or shut down. This is the fundamental prerequisite for any PoE deployment.

Answer

The switch supports LLDP-MED for power negotiation.

Answer

All PoE devices are from the same manufacturer.

Answer

The cable length does not exceed 150 meters.

Question 6

A network has a single switch with VLANs 10, 20, and 30 configured. The switch is connected to a router that has three subinterfaces, each in a different VLAN. How many broadcast domains are present?

Accepted Answer

3. Each VLAN is a separate Layer 2 broadcast domain. With VLANs 10, 20, and 30 configured on the switch and a router using subinterfaces to route between them, there are exactly three broadcast domains — one per VLAN. Broadcasts are confined to their VLAN and do not cross VLAN boundaries without a Layer 3 device.

Answer

1

Answer

4

Answer

5

Question 7

A network engineer needs to connect two switches located 400 meters apart. The cable run includes high electromagnetic interference from nearby machinery. The engineer decides to use fiber optic cabling. Which transceiver type and fiber combination should be used to ensure the link reaches 400 meters while remaining cost-effective?

Accepted Answer

Multimode fiber with 1000BASE-SX transceivers. 1000BASE-SX transceivers over multimode fiber (typically OM2 or OM3) can reliably reach 400 meters at 1 Gbps, and this combination is cost-effective for short-to-medium distances. Multimode fiber uses a larger core that is cheaper to terminate and pair with lower-cost VCSEL-based SX optics, making it ideal for runs under 550 meters in environments with high EMI.

Answer

Single-mode fiber with 1000BASE-LX transceivers

Answer

Multimode fiber with 10GBASE-SR transceivers

Answer

Single-mode fiber with 1000BASE-EX transceivers

Question 8

A network engineer is configuring a new wireless LAN for a high-density environment such as a conference hall. The engineer needs to minimize co-channel interference. Which of the following should be configured on the access points?

Accepted Answer

Decrease transmit power. In a high-density environment like a conference hall, decreasing transmit power on access points reduces the cell size, which allows for more APs to be placed closer together without their coverage areas overlapping excessively. This minimizes co-channel interference by ensuring that APs on the same channel are physically separated, improving overall throughput and client performance.

Answer

Increase transmit power

Answer

Decrease beacon interval

Answer

Implement channel bonding

Question 9

A network administrator is configuring OSPF on a router that has interfaces in only one area and does not perform route redistribution. Which OSPF router type best describes this router?

Accepted Answer

Internal router. An internal router has all its interfaces in a single OSPF area and does not perform route redistribution. Since the router's interfaces are confined to one area and it does not connect to other routing domains, it fits the definition of an internal router. This type of router maintains a single link-state database for that area and does not generate Type 3 or Type 5 LSAs.

Answer

Backbone router

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Area Border Router (ABR)

Answer

Autonomous System Boundary Router (ASBR)

Question 10

A user calls the help desk stating that they cannot access any network resources. The technician asks the user to run ipconfig and the output shows an IP address of 169.254.15.20 with a subnet mask of 255.255.0.0. Which of the following is the most likely cause?

Accepted Answer

The DHCP server is unreachable. The IP address 169.254.15.20 with a subnet mask of 255.255.0.0 is an Automatic Private IP Addressing (APIPA) address, which Windows assigns when a DHCP client fails to receive a lease from a DHCP server. Since the user cannot access any network resources, the most likely cause is that the DHCP server is unreachable, preventing the client from obtaining a valid IP address, default gateway, and DNS server settings.

Answer

The DNS server is not responding

Answer

The default gateway is misconfigured

Answer

There is a duplicate IP address on the network