N10-009 Practice Test 34 — 15 Questions

Question 1

A network technician is explaining the OSI model to a junior technician. The technician mentions that the Transport layer is responsible for end-to-end communication and data segmentation. Which protocol operates at the Transport layer?

Accepted Answer

TCP. TCP (Transmission Control Protocol) operates at Layer 4 (Transport) of the OSI model, providing reliable, connection-oriented end-to-end communication and data segmentation with sequencing and acknowledgment. It ensures data is delivered error-free and in order, directly fulfilling the described responsibilities.

Answer

IP

Answer

Ethernet

Answer

HTTP

Question 2

A network technician configures an 802.1Q trunk link between two switches. After the configuration, VLAN 20 traffic is not passing across the trunk, although VLAN 10 traffic works fine. The technician verifies that both switches have VLAN 20 created and that the trunk is up. What is the most likely cause?

Accepted Answer

VLAN 20 is not included in the allowed VLAN list on the trunk.. The most likely cause is that VLAN 20 is not included in the allowed VLAN list on the trunk. By default, an 802.1Q trunk allows all VLANs, but if the allowed VLAN list has been manually configured or pruned, VLAN 20 may have been excluded. Since VLAN 10 works, the trunk is operational, and both switches have VLAN 20 created, the issue is specifically that the trunk is not permitting VLAN 20 traffic.

Answer

The native VLAN is mismatched between the switches.

Answer

The trunk port is set to dynamic desirable mode.

Answer

The encapsulation type is ISL instead of 802.1Q.

Question 3

A network switch forwards frames based on which address?

Accepted Answer

MAC address. A network switch operates at Layer 2 (Data Link Layer) of the OSI model and uses MAC addresses to make forwarding decisions. When a frame arrives, the switch examines the destination MAC address, looks it up in its MAC address table (CAM table), and forwards the frame only to the port associated with that MAC address, reducing collision domains and improving network efficiency.

Answer

IP address

Answer

Port number

Answer

Domain name

Question 4

A network technician is troubleshooting an issue where Server A can ping Server B by IP address, but Server B cannot ping Server A. Both servers are in the same VLAN and subnet, connected to the same switch. The switch ports are configured identically, and there are no ACLs or firewalls between them. Which of the following is the MOST likely cause?

Accepted Answer

Server A's firewall is blocking incoming ICMP. Server A can ping Server B by IP address, meaning ICMP echo requests from Server A reach Server B and echo replies return successfully. However, Server B cannot ping Server A, which indicates that ICMP echo requests from Server B are not reaching Server A or their replies are blocked. Since both servers are in the same VLAN/subnet with no ACLs or firewalls between them, the most likely cause is that Server A's host-based firewall is blocking incoming ICMP (echo requests), preventing Server B's pings from being processed. This is a classic symptom of a one-way firewall rule that permits outbound ICMP but denies inbound ICMP.

Answer

Server B's firewall is blocking outgoing ICMP

Answer

The cable connecting Server A is faulty

Answer

There is a duplex mismatch on Server B's switch port

Question 5

Match each wireless standard to its maximum theoretical speed.

Question 6

Match each IEEE 802.3 standard to its description.

Question 7

Match each network device to its primary function.

Question 8

A network administrator needs to upgrade the firmware on a core switch. According to change management best practices, which step should be performed first?

Accepted Answer

Submit a change request. According to change management best practices, the first step in any network change is to submit a change request (option C). This ensures the proposed firmware upgrade is reviewed, approved, and documented before any technical actions are taken, reducing the risk of unplanned outages and providing a rollback plan. Skipping this step violates ITIL/change management frameworks and can lead to unauthorized changes that impact network stability.

Answer

Download the new firmware

Answer

Create a backup of the current configuration

Answer

Schedule a maintenance window

Question 9

Match each network protocol to its well-known port number.

Question 10

A network technician needs to back up the configuration file of a managed switch to a central server on a regular basis. The switch supports a simple and widely used protocol for this purpose. Which of the following protocols should the technician use?

Accepted Answer

A: TFTP. TFTP (Trivial File Transfer Protocol) is the correct choice because it is a simple, lightweight protocol designed specifically for transferring configuration files to and from network devices like managed switches. It uses UDP port 69 and requires no authentication or complex session setup, making it ideal for automated backup scripts that run on a regular basis. While it lacks security features, its simplicity and widespread support in network equipment firmware make it the standard for this purpose.

Answer

B: HTTP

Answer

C: SNMP

Answer

D: SSH

Question 11

A network technician needs to find which physical patch panel port in the server room connects to a specific office wall jack. Which type of network documentation should the technician consult?

Accepted Answer

Cabling diagram. A cabling diagram provides the physical layer (Layer 1) documentation that maps specific patch panel ports to wall jacks, including cable runs, termination points, and labeling. This is exactly what the technician needs to trace the physical connection from the server room patch panel to the office wall jack.

Answer

Logical topology diagram

Answer

Network baseline

Answer

Rack diagram

Question 12

A security analyst is investigating a potential data exfiltration. The analyst notices that a server is sending DNS queries to an external IP address on TCP port 53, and the DNS responses are unusually large. The server is not a DNS server. Which technique is most likely being used?

Accepted Answer

DNS tunneling. DNS tunneling encodes non-DNS data (e.g., exfiltrated files) within DNS queries and responses, often using TCP port 53 to bypass firewalls. The unusually large responses are a hallmark of tunneled data being returned in DNS payloads, and the fact that the server is not a DNS server strongly indicates it is being used as a client for covert data transfer.

Answer

DNS amplification attack

Answer

DNS zone transfer

Answer

DNS cache poisoning

Question 13

A security administrator discovers that an attacker has intercepted data between two legitimate hosts by redirecting traffic through a rogue device. Which type of attack is this?

Accepted Answer

Man-in-the-middle. This is a classic man-in-the-middle (MITM) attack, where the attacker intercepts and potentially alters communication between two legitimate hosts by inserting a rogue device into the data path. The key characteristic is the redirection of traffic through the attacker's device, which allows them to capture, inspect, or modify packets in transit.

Answer

ARP poisoning

Answer

DNS poisoning

Answer

Replay attack

Question 14

A network administrator is planning a maintenance window to upgrade the firmware on critical switches. Which step should the administrator perform first to ensure minimal downtime?

Accepted Answer

Test the new firmware in a lab environment. Option D is correct because testing the new firmware in a lab environment first validates compatibility and stability without risking production network downtime. This step identifies potential issues such as configuration incompatibilities or hardware-specific bugs before the maintenance window, ensuring a smooth upgrade process.

Answer

Download the firmware from the vendor website

Answer

Back up the current configuration and firmware image

Answer

Notify users of the upcoming maintenance

Question 15

A network technician is troubleshooting communication between two switches. The trunk link between them is up, and both switches have the same list of allowed VLANs. However, devices in VLAN 10 on one switch cannot communicate with devices in VLAN 10 on the other switch. What is the MOST likely cause of this issue?

Accepted Answer

Native VLAN mismatch. A native VLAN mismatch is the most likely cause because when two switches have different native VLANs configured on a trunk, they will incorrectly tag or fail to tag frames for that VLAN. In this scenario, devices in VLAN 10 cannot communicate because the native VLAN frames (which are sent untagged) are being dropped or misinterpreted by the receiving switch, even though both switches list VLAN 10 as allowed. The trunk is up and the allowed VLAN list matches, so the issue points directly to a mismatch in the native VLAN configuration.

Answer

Speed or duplex mismatch

Answer

Spanning Tree Protocol blocking the port

Answer

VLAN 10 is not created on one of the switches