N10-009 Practice Test 3 — 10 Questions

Question 1

A network administrator is troubleshooting communication between two switches connected via a trunk port. The trunk link is up/up, but devices in VLAN 20 cannot communicate across the trunk. The administrator has verified that both switches have VLAN 20 created and that the access ports are configured correctly. Which command should the administrator run on each switch to verify the trunk's allowed VLAN list?

Accepted Answer

show interfaces trunk. The 'show interfaces trunk' command displays the trunking status, including the allowed VLAN list on the trunk port. Since the trunk link is up/up but VLAN 20 traffic fails, the most likely cause is that VLAN 20 is not included in the allowed VLAN list on one or both switches. This command directly shows which VLANs are permitted, pruned, or active on the trunk.

Answer

show vlan brief

Answer

show running-config interface

Answer

show mac address-table

Question 2

A network administrator wants to ensure that only authorized devices can access the network on a switch port. The administrator has a list of allowed MAC addresses. Which security feature should be enabled on the switch port?

Accepted Answer

Port security. Port security is the correct feature because it allows the administrator to specify a list of allowed MAC addresses per switch port. When a device with an unauthorized MAC address attempts to connect, the switch can either block the traffic, generate an alert, or disable the port (errdisable state). This directly enforces access control based on the MAC address list provided.

Answer

802.1X

Answer

MAC address filtering

Answer

VLAN hopping prevention

Question 3

A network administrator is configuring BGP between two autonomous systems. Which BGP attribute is primarily used to influence inbound traffic to a particular AS?

Accepted Answer

MED (Multi-Exit Discriminator). The Multi-Exit Discriminator (MED) is a BGP attribute used to influence inbound traffic from a neighboring AS when multiple entry points exist. A lower MED value is preferred, allowing an AS to advertise to its neighbor which path should be used to reach it, thereby influencing traffic entering the local AS.

Answer

AS_PATH

Answer

Next Hop

Answer

Local Preference

Question 4

A network administrator needs to be notified immediately when the CPU utilization on a core router exceeds 90%. Which SNMP mechanism should be configured on the router?

Accepted Answer

SNMP trap. B is correct because SNMP traps are unsolicited notifications sent from an SNMP agent (the router) to the manager when a predefined condition occurs, such as CPU utilization exceeding 90%. This allows immediate notification without waiting for the manager to poll, which is essential for urgent alerts.

Answer

SNMP get

Answer

SNMP walk

Answer

SNMP set

Question 5

A network device receives a frame on one port and forwards it out to all other ports. The device does not examine the destination MAC address. Which type of device is being described?

Accepted Answer

Hub. A hub operates at Layer 1 (physical layer) of the OSI model and simply repeats incoming electrical or optical signals out all other ports without any processing of the frame's destination MAC address. This behavior matches the description exactly: the device receives a frame on one port and forwards it out all other ports without examining the MAC address.

Answer

Switch

Answer

Bridge

Answer

Router

Question 6

A network administrator is configuring a monitoring system to collect metrics from network devices. The administrator needs to ensure that the monitoring system can automatically discover the devices and obtain detailed information about their configuration and status, such as interface descriptions and software versions. Which protocol is best suited for this purpose?

Accepted Answer

SNMP. SNMP (Simple Network Management Protocol) is the correct choice because it is specifically designed for network management and monitoring. It allows a management system to automatically discover devices (via SNMP walks or queries to MIBs) and retrieve detailed configuration and status information, such as interface descriptions and software versions, by reading OIDs from the device's MIB. This matches the requirement for automatic discovery and detailed data collection.

Answer

LLDP

Answer

NetFlow

Answer

Syslog

Question 7

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 8

A network administrator is creating a new VLAN that will contain 20 devices. The administrator wants to use the most efficient subnet that provides enough usable IP addresses while minimizing waste. Which of the following subnet masks should be used?

Accepted Answer

255.255.255.224 (/27). A /27 subnet mask (255.255.255.224) provides 32 total addresses, of which 30 are usable (2^5 - 2 = 30). This is the most efficient choice for 20 devices because it offers exactly enough usable IPs with minimal waste (only 10 unused addresses), whereas a /28 would provide only 14 usable addresses (insufficient) and a /29 would provide only 6 usable addresses (also insufficient).

Answer

255.255.255.240 (/28)

Answer

255.255.255.248 (/29)

Answer

255.255.255.192 (/26)

Question 9

A network administrator is implementing a change management process. Which of the following is the PRIMARY benefit of following this process?

Accepted Answer

It minimizes the impact of changes on network operations and reduces errors. The primary benefit of a change management process is to minimize the impact of changes on network operations and reduce errors. By requiring documented planning, approval, and rollback procedures, change management ensures that modifications are reviewed and tested before implementation, which directly reduces the risk of misconfigurations and unplanned outages.

Answer

It reduces the cost of implementing new hardware

Answer

It ensures that all network changes are automated

Answer

It documents the network topology for future reference

Question 10

A network administrator needs to power IP phones and wireless access points through the Ethernet cable. Which standard should be supported?

Accepted Answer

802.3af. The 802.3af standard, also known as Power over Ethernet (PoE), delivers up to 15.4 watts of DC power over twisted-pair Ethernet cabling. This allows devices like IP phones and wireless access points to receive both data and power through a single Ethernet cable, eliminating the need for separate power supplies.

Answer

802.11ac

Answer

802.1X

Answer

802.3ab