N10-009 Network Implementation — 25 Questions

Question 1

Match each OSI layer to its description.

Question 2

Match each network service to its description.

Question 3

A network engineer needs to segment a single physical switch into multiple broadcast domains to improve security and reduce traffic. Which technology should be implemented?

Accepted Answer

Virtual LAN (VLAN). A VLAN (Virtual LAN) segments a physical switch into multiple isolated broadcast domains at Layer 2. By assigning ports to different VLANs, broadcast traffic is confined to each VLAN, improving security and reducing unnecessary traffic. This directly meets the requirement without requiring additional hardware.

Answer

Spanning Tree Protocol (STP)

Answer

VLAN Trunking Protocol (VTP)

Answer

Access Control List (ACL)

Question 4

A router receives a packet destined for 10.0.0.15. It has the following routes in the routing table: 10.0.0.0/8 via 192.168.1.1, 10.0.0.0/16 via 192.168.2.1, 0.0.0.0/0 via 192.168.3.1. Which route will be used?

Accepted Answer

10.0.0.0/16 via 192.168.2.1. The router will use the route 10.0.0.0/16 via 192.168.2.1 because it has the longest prefix match (16 bits) for the destination 10.0.0.15. The /16 route is more specific than the /8 route and the default route, so it is preferred regardless of administrative distance or metric.

Answer

Default route (0.0.0.0/0)

Answer

10.0.0.0/8 via 192.168.1.1

Answer

None; the packet is dropped

Question 5

A company has just installed a new fiber optic connection between two buildings 2 km apart. The connection is using multimode fiber. However, the signal is too weak at the receiving end. What is the most likely cause?

Accepted Answer

Attenuation due to distance. Multimode fiber (MMF) is designed for shorter distances, typically up to 550 meters for 10 Gbps (OM3/OM4) and up to 2 km only for lower speeds like 100 Mbps or 1 Gbps using older OM1/OM2 fiber. At 2 km, the signal attenuation exceeds the power budget of the MMF link, causing a weak signal at the receiver. Single-mode fiber (SMF) would be required for reliable transmission over this distance.

Answer

Electromagnetic interference

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Incorrect termination

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Crosstalk

Question 6

A small office uses a wireless router that provides both wired and wireless connectivity. The router's LAN IP is 192.168.1.1. A new printer with a static IP of 192.168.1.50 cannot be reached from a laptop obtaining an IP via DHCP. The laptop's IP is 192.168.1.100. Which of the following is the most likely cause?

Accepted Answer

The subnet mask is incorrect. The laptop obtains an IP address via DHCP, which typically assigns a subnet mask of 255.255.255.0 for a /24 network. If the printer has a static IP of 192.168.1.50 but is configured with an incorrect subnet mask (e.g., 255.255.255.252), the printer may believe it is on a different subnet than the laptop (192.168.1.100). This prevents the laptop from reaching the printer because the printer will not respond to ARP requests or will send traffic to its default gateway instead of directly to the laptop.

Answer

The printer is on a different VLAN

Answer

The default gateway is misconfigured

Answer

The DHCP scope is exhausted

Question 7

A network engineer has established an IPsec VPN tunnel between a branch office (10.0.0.0/24) and the main office (192.168.10.0/24). The tunnel shows as up and active, but users at the branch office cannot ping the main office server at 192.168.10.10. The main office can ping the branch office gateway successfully. What is the most likely cause of this issue?

Accepted Answer

Incorrect static route on the branch router for the 192.168.10.0/24 network. The tunnel is up and active, and the main office can ping the branch office gateway, which confirms that Phase 1 and Phase 2 of IPsec are correctly negotiated and that the tunnel is passing traffic from the main office toward the branch. However, branch users cannot reach 192.168.10.10, indicating that return traffic from the branch is not being routed into the tunnel. The most likely cause is that the branch router lacks a static route for 192.168.10.0/24 pointing to the tunnel interface (or the IPsec virtual interface), so packets from the branch destined for the main office are sent out the wrong interface or dropped instead of being encrypted and forwarded through the VPN.

Answer

Mismatched encryption algorithms between the two VPN peers

Answer

Firewall on the main office server blocking ICMP

Answer

Incorrect IKE authentication settings

Question 8

A network administrator adds a new server to VLAN 20. The switch port is configured as an access port in VLAN 20, and the server has a correct static IP address in that subnet. However, the server cannot communicate with other devices in the same VLAN. The VLAN exists on the switch and other devices in VLAN 20 are working. What is the most likely cause of this issue?

Accepted Answer

The switch port is configured as a trunk port instead of an access port. The scenario states the switch port is configured as an access port in VLAN 20, but the server cannot communicate with other devices in the same VLAN. If the port were actually configured as a trunk port, it would expect frames to be tagged with a VLAN ID. An untagged frame from the server would be placed into the native VLAN (typically VLAN 1), not VLAN 20, causing a mismatch. This explains why the server, despite having a correct static IP in VLAN 20's subnet, cannot reach other devices in VLAN 20.

Answer

VLAN 20 is not allowed on the trunk to the router

Answer

The server does not have a default gateway configured

Answer

The port is administratively down

Question 9

A network administrator has just connected a new access switch to the core switch via a trunk port. The administrator configured the trunk port on both switches with the same allowed VLAN list. However, hosts on VLAN 10 connected to the new access switch cannot communicate with hosts on VLAN 10 on the core switch. The trunk is operational and shows up/up. What is the most likely cause?

Accepted Answer

A) VLAN 10 has not been created on the new access switch. The most likely cause is that VLAN 10 has not been created on the new access switch. Even though the trunk port is up/up and the allowed VLAN list matches, a switch will not forward traffic for a VLAN that does not exist in its local VLAN database. Without the VLAN being created, the switch drops all frames tagged with VLAN 10, preventing communication between hosts on that VLAN across the trunk.

Answer

B) Native VLAN mismatch on the trunk

Answer

C) Trunk encapsulation mismatch (ISL vs 802.1Q)

Answer

D) STP is blocking the VLAN 10 traffic on the trunk

Question 10

A company is deploying a new wireless network in a warehouse. The network administrator needs to ensure that clients can seamlessly roam between access points without losing connectivity. Which of the following should be configured?

Accepted Answer

A) Same SSID and security settings on all APs. Configuring the same SSID and security settings on all access points (APs) is essential for seamless roaming because clients use the SSID to identify the network and the security credentials to authenticate. When a client moves between APs, it can re-associate without needing to re-authenticate or discover a new network, provided the SSID and security parameters (e.g., PSK or 802.1X configuration) are identical. This ensures a smooth handoff and maintains connectivity during roaming.

Answer

B) Different channels per AP to reduce interference

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C) WPA2-Enterprise with RADIUS authentication

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D) Mesh topology for AP interconnection

Question 11

A company is setting up a new branch office and needs to connect it to the main office over the internet using a secure VPN. The branch office has a dynamic public IP address. Which type of VPN should be configured?

Accepted Answer

Dynamic Multipoint VPN (DMVPN). C is correct because Dynamic Multipoint VPN (DMVPN) is designed to handle sites with dynamic public IP addresses, such as a branch office with a dynamically assigned IP. DMVPN uses mGRE (multipoint Generic Routing Encapsulation) and NHRP (Next Hop Resolution Protocol) to dynamically establish tunnels between spoke routers without requiring static IP configurations on each spoke, making it ideal for this scenario.

Answer

Site-to-site IPsec VPN with static IPs

Answer

Remote access VPN using SSL

Answer

Policy-based VPN

Question 12

A company is implementing a wireless network and needs to support high-density client environments with minimal interference. Which IEEE 802.11 standard operates in the 5 GHz band and provides the highest throughput among the options?

Accepted Answer

802.11ac. 802.11ac (Wi-Fi 5) operates exclusively in the 5 GHz band and supports up to 8 spatial streams, 256-QAM modulation, and channel bonding up to 160 MHz, yielding theoretical throughput exceeding 6.9 Gbps. This makes it the highest-throughput option among the listed standards for high-density environments with minimal interference, as the 5 GHz band offers more non-overlapping channels and less co-channel contention than 2.4 GHz.

Answer

802.11n

Answer

802.11g

Answer

802.11b

Question 13

A company is deploying a wireless network that must support both 2.4 GHz and 5 GHz frequency bands. Which IEEE 802.11 standard supports both bands and is backward compatible with older devices?

Accepted Answer

C) 802.11n. 802.11n (Wi-Fi 4) is the correct answer because it was the first standard to natively support both 2.4 GHz and 5 GHz bands simultaneously, using MIMO (Multiple Input Multiple Output) technology. It also maintains backward compatibility with older 802.11a/b/g devices through mandatory support for legacy modulation schemes (DSSS/CCK for 2.4 GHz and OFDM for 5 GHz).

Answer

A) 802.11b

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B) 802.11g

Answer

D) 802.11ac

Question 14

A network engineer has configured an IPsec site-to-site VPN between two offices. The tunnel is established and shows as active. However, users at the branch office (10.0.1.0/24) cannot reach servers at the main office (192.168.1.0/24). Both routers have the correct VPN policies and firewall rules permitting IPsec traffic. What should the engineer check next?

Accepted Answer

B) That the routing tables on both routers include routes to the remote subnet. The tunnel being active means Phase 1 and Phase 2 of IPsec are established, but traffic still cannot flow because the routers lack routes to the remote subnets. Without a route for 10.0.1.0/24 on the main office router (or 192.168.1.0/24 on the branch router), packets will be dropped or sent out the wrong interface, even though the VPN policy and firewall rules are correct. The engineer must verify that static routes or a dynamic routing protocol (e.g., OSPF over the tunnel) are in place to direct traffic into the IPsec tunnel interface.

Answer

A) That the DNS server addresses are correctly configured

Answer

C) That the MTU size is set to 1500 on both ends

Answer

D) That the SSID is correctly configured on the access points

Question 15

A network administrator connects a new access switch to the core switch via a trunk port. Both switches have the same VLAN database, and the trunk is configured to allow all VLANs. However, hosts on VLAN 10 connected to the new access switch cannot communicate with hosts on VLAN 10 on the core switch. The administrator verifies that the access ports for VLAN 10 are correctly configured and that the trunk link status is up/up. Which of the following is the most likely cause?

Accepted Answer

The native VLAN on the trunk port is different on the two switches.. When the native VLAN (typically VLAN 1 by default) is mismatched on a trunk link, the switches will not properly tag frames for that VLAN. Since VLAN 10 is not the native VLAN, a native VLAN mismatch does not directly block VLAN 10 traffic; however, the scenario states that both switches have the same VLAN database and the trunk allows all VLANs, so the most likely cause is a native VLAN mismatch that can cause control plane issues or miscommunication. In practice, a native VLAN mismatch can lead to VLAN 10 hosts being unable to communicate because the switches may place the native VLAN frames into different VLANs, disrupting Layer 2 connectivity for all VLANs including VLAN 10.

Answer

The trunk port is in an err-disabled state.

Answer

The switchport mode is not set to trunk on one side.

Answer

The spanning-tree protocol is blocking VLAN 10 on the trunk.

Question 16

A network engineer has successfully established an IPsec site-to-site VPN tunnel between a branch office (10.0.1.0/24) and the main office (192.168.1.0/24). The tunnel status shows as active, and both sides can ping each other's tunnel interface IP addresses. However, users at the branch office cannot ping the main office server at 192.168.1.10, and the main office cannot ping the branch office server at 10.0.1.10. The firewall rules on both sides permit IPsec traffic and all internal traffic. What should the engineer check NEXT?

Accepted Answer

Verify routing entries on both routers to ensure the remote internal subnets are reachable via the tunnel.. The tunnel is active and both sides can ping each other's tunnel interface IPs, confirming that IPsec phase 1 and phase 2 are established and the tunnel itself is functional. However, users cannot reach the remote internal subnets (10.0.1.0/24 and 192.168.1.0/24), which indicates a routing problem: the routers likely lack routes for those remote subnets pointing to the tunnel interface. Without proper routing entries, traffic destined for the remote LAN is sent out the wrong interface or dropped, even though the tunnel is up.

Answer

Check the IPsec security associations for encryption algorithm mismatch.

Answer

Disable the firewall on the internal interfaces temporarily.

Answer

Regenerate the pre-shared key on both sides.

Question 17

A network administrator is connecting two switches and wants to increase the bandwidth between them while also providing redundancy in case one link fails. Which technology should be configured on the switch ports?

Accepted Answer

Link Aggregation Control Protocol (LACP). Link Aggregation Control Protocol (LACP) allows multiple physical links between two switches to be combined into a single logical link, increasing aggregate bandwidth and providing redundancy: if one physical link fails, traffic continues over the remaining links. This directly meets the requirement for both higher bandwidth and link-level fault tolerance.

Answer

Spanning Tree Protocol (STP)

Answer

VLAN trunking (802.1Q)

Answer

Power over Ethernet (PoE)

Question 18

A network administrator is configuring dynamic routing between two routers in the same organization. The routers must support VLSM, converge quickly, and use a metric that is based on bandwidth and delay. Which routing protocol should be configured?

Accepted Answer

EIGRP. C is correct because EIGRP is a Cisco-proprietary hybrid routing protocol that supports Variable-Length Subnet Masking (VLSM), converges rapidly using the Diffusing Update Algorithm (DUAL), and uses a composite metric that by default includes bandwidth and delay. This makes it ideal for the scenario where both VLSM support and fast convergence are required with a metric based on bandwidth and delay.

Answer

RIP

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OSPF

Answer

BGP

Question 19

A company is deploying a new wireless network for a small office. The network will consist of three access points. The IT manager wants the APs to automatically coordinate radio frequency settings and client roaming without a dedicated controller. Which technology should be implemented?

Accepted Answer

Cloud-managed access points. Cloud-managed access points (APs) are the correct choice because they can automatically coordinate radio frequency (RF) settings and client roaming without a dedicated on-premises controller. The cloud-based management platform handles channel selection, power adjustment, and fast roaming (e.g., 802.11r/k/v) by communicating with each AP over the internet, making it ideal for a small office with only three APs.

Answer

Mesh network

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Controller-based wireless

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Standalone APs

Question 20

A company is extending its network to a new building located 200 meters away. The link must support 1 Gbps speeds. Which cabling type should be used?

Accepted Answer

Single-mode fiber. Single-mode fiber (SMF) is the correct choice because it supports 1 Gbps speeds over distances far exceeding 200 meters, typically up to 5 km or more using 1000BASE-LX optics. Copper cabling like Cat5e and Cat6 is limited to a maximum segment length of 100 meters for 1 Gbps (1000BASE-T), making them unsuitable for this 200-meter link.

Answer

Cat5e

Answer

Cat6

Answer

Coaxial cable