N10-009 Free Practice Questions — Page 21 (2026)

Question 198

Which of the following kinds of targeted attacks uses multiple computers or bots to request the same resource repeatedly?

A. On-path

B. DDoS

C. ARP spoofing

D. MAC flooding

Show Answer

Correct Answer: B

Explanation:
A Distributed Denial of Service (DDoS) attack uses multiple computers or bots, typically coordinated as a botnet, to send repeated requests to the same resource, overwhelming it and preventing legitimate access. The other options involve different network attack techniques that do not rely on many systems flooding a resource.

Question 199

Which of the following is the most cost-effective way to safely expand outlet capacity in an IDF?

A. PDU

B. Surge protector

C. UPS

D. Power strip

Show Answer

Correct Answer: A

Explanation:
In an IDF, a rack-mounted Power Distribution Unit (PDU) is purpose-built to safely and efficiently expand outlet capacity for network and server equipment. PDUs are designed for continuous operation, proper grounding, and load handling in IT environments, making them more cost-effective and appropriate than a UPS (which is for backup power), a surge protector (limited outlet expansion and not rack-focused), or a basic power strip (often not rated for critical or continuous use).

Question 200

A network administrator is creating a subnet that will include 45 separate hosts on a small private network within a large network architecture. Which of the following options is the most efficient use of network addresses when assigning this network?

A. 10.0.50.128/25

B. 10.7.142.128/27

C. 10.152.4.192/26

D. 10.192.1.64/28

Show Answer

Correct Answer: C

Explanation:
The subnet must support at least 45 usable host IP addresses. A /26 subnet provides 64 total addresses, with 62 usable hosts after excluding the network and broadcast addresses, making it the smallest and most efficient option that meets the requirement. A /25 provides far more addresses than needed, while /27 and /28 do not provide enough usable hosts.

Question 201

A network technician is troubleshooting an issue between a web server and computers within a LAN. The technician needs to gather information about the IP addresses, protocols, and content of the traffic. Which of the following will best help the technician troubleshoot the issue?

A. Flow data

B. SNMP traps

C. Packet capture

D. Server logs

Show Answer

Correct Answer: C

Explanation:
Packet capture provides the most detailed visibility into network traffic, including source and destination IP addresses, protocols in use, and the actual packet payload/content. This level of detail is necessary to analyze and troubleshoot communication issues between a web server and LAN clients. Flow data, SNMP traps, and server logs do not provide full packet-level content.

Question 202

Which of the following layers in the OSI model is responsible for establishing, maintaining, and terminating connections between nodes?

A. Physical

B. Network

C. Session

D. Transport

Show Answer

Correct Answer: C

Explanation:
In the OSI model, the Session layer (Layer 5) is responsible for establishing, managing, and terminating sessions (connections) between applications on different hosts. The Physical layer handles signaling, the Network layer handles routing, and the Transport layer focuses on end-to-end data delivery and reliability rather than session control.

Question 203

Which of the following protocols is commonly associated with TCP port 443?

A. Telnet

B. SMTP

C. HTTPS

D. SNMP

Show Answer

Correct Answer: C

Explanation:
TCP port 443 is the standard port used by HTTPS (Hypertext Transfer Protocol Secure), which provides encrypted web communication. Telnet typically uses port 23, SMTP uses port 25, and SNMP commonly uses ports 161/162.

Question 204

A network engineer configures the network settings in a new server as follows: IP address = 192.168.1.15 - Subnet mask = 255.255.255.0 - Gateway = 192.168.1.255 - The server can reach other hosts on the same subnet successfully, but it cannot reach hosts on different subnets. Which of the following is most likely configured incorrectly?

A. Subnet mask

B. Gateway

C. Default route

D. IP address

Show Answer

Correct Answer: B

Explanation:
The configured gateway 192.168.1.255 is the broadcast address for the 192.168.1.0/24 subnet and cannot function as a default gateway. A gateway must be a valid host IP on the local subnet (e.g., 192.168.1.1). This explains why the server can reach local hosts but not remote networks.

Question 205

A network engineer is designing an internal network that needs to support both IPv4 and IPv6 routing. Which of the following routing protocols is capable of supporting both IPv4 and IPv6?

A. OSPFv3

B. RIPv2

C. BGP

D. EIGRP

Show Answer

Correct Answer: A, C, D

Explanation:
OSPFv3 supports both IPv4 and IPv6 via address families, BGP supports IPv4 and IPv6 using multiprotocol extensions (MP-BGP), and EIGRP supports both IPv4 and IPv6 (either as separate instances or via named mode). RIPv2 does not support IPv6; RIPng is required for IPv6.

Question 206

A network administrator needs to efficiently deploy 200 systems using RFC1918 addresses. Which of the following networks should the administrator use?

A. 10.10.10.0/8

B. 150.200.1.0/24

C. 192.168.1.0/24

D. 254.169.0.0/24

Show Answer

Correct Answer: C

Explanation:
RFC1918 private address ranges are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. Option C (192.168.1.0/24) is within a valid private range and provides 254 usable host addresses, which is sufficient and efficient for deploying 200 systems. The other options are either public address space or not RFC1918-compliant.

Question 207

A network administrator deploys several new desk phones and workstation cubicles. Each cubicle has one assigned switchport. The administrator run the following commands: switchport mode access switchport voice vlan 69 With which of the following VLANs will the workstation traffic be tagged?

A. Private VLAN

B. Voice VLAN

C. Native VLAN

D. Data VLAN

Show Answer

Correct Answer: D

Explanation:
On an access port configured with `switchport mode access` and `switchport voice vlan 69`, Cisco switches treat voice and data traffic differently. Voice traffic from the IP phone is tagged with VLAN 69. Workstation (PC) traffic remains untagged and is associated with the port’s access (data) VLAN. If no `switchport access vlan` command is configured, that access/data VLAN defaults to VLAN 1. Thus, the workstation traffic belongs to the data VLAN, not the voice VLAN or native VLAN.