N10-009 Practice Test 14 — 15 Questions

Question 1

A network administrator needs to monitor the health and performance of network devices and receive alerts when link failures occur. Which of the following protocols should be implemented?

Accepted Answer

SNMP. SNMP (Simple Network Management Protocol) is the correct choice because it is specifically designed to monitor and manage network devices, collect performance metrics, and send traps or notifications when events like link failures occur. SNMP agents on devices report status to a management system, which can generate alerts based on thresholds or trap messages (e.g., linkDown traps per RFC 3418).

Answer

SMTP

Answer

SSH

Answer

TFTP

Question 2

A user reports that they can browse to a website by typing its IP address (e.g., 93.184.216.34) but cannot access it by typing the domain name (e.g., www.example.com). The user's workstation receives IP configuration via DHCP. Which of the following is the most likely cause?

Accepted Answer

The DNS server address is incorrect or unreachable.. The user can reach the website by IP address but not by domain name, which isolates the issue to name resolution. DNS translates domain names to IP addresses; if the DNS server address provided by DHCP is incorrect or unreachable, the workstation cannot resolve www.example.com to 93.184.216.34. This is the most likely cause because all other connectivity (default gateway, web server) is confirmed working by the successful IP-based access.

Answer

The default gateway is misconfigured.

Answer

The web server's SSL certificate is expired.

Answer

The workstation's hosts file has an incorrect entry.

Question 3

Match each OSI layer to its description.

Accepted Answer

Physical Layer: Transmits raw bits over a physical medium.. The correct matches are: Physical layer transmits raw bits, Network layer routes with logical addressing, and Application layer supports user applications. Common confusions involve swapping the roles of Data Link and Transport layers.

Answer

Data Link Layer: Provides end-to-end communication and error recovery.

Answer

Transport Layer: Provides reliable node-to-node communication.

Question 4

A network administrator configures a router-on-a-stick to route traffic between VLAN 10 and VLAN 20. Users in each VLAN can communicate within their own VLAN but cannot reach devices in the other VLAN. The router has subinterfaces configured, and the switch port connected to the router is configured as an access port in VLAN 1. What is the most likely cause of the inter-VLAN connectivity failure?

Accepted Answer

The switch port connected to the router is not configured as a trunk.. The router-on-a-stick design requires the switch port connecting to the router to be configured as a trunk port. This allows the switch to forward frames from multiple VLANs (VLAN 10 and VLAN 20) to the router's subinterfaces, each tagged with the appropriate 802.1Q VLAN ID. When the port is set as an access port in VLAN 1, it only accepts untagged frames from VLAN 1, so the router's subinterfaces for VLAN 10 and VLAN 20 never receive traffic, breaking inter-VLAN routing.

Answer

The router's subinterfaces are not configured with IP addresses.

Answer

The VLANs are not created on the switch.

Answer

The router's default route is missing.

Question 5

A user at a branch office reports that they cannot connect to a file server at the main office. The branch office connects to the main office via a site-to-site VPN, and the VPN tunnel shows as active. The user can ping the main office's default gateway but not the file server. Which of the following should the technician check NEXT?

Accepted Answer

A) Check the routing tables on the branch router. The VPN tunnel is active and the user can ping the main office's default gateway, which confirms that Layer 3 connectivity exists across the tunnel. However, the file server is unreachable, indicating that the traffic destined for the file server's subnet is not being forwarded correctly. The next logical step is to check the routing tables on the branch router to ensure there is a specific route (or a default route) pointing to the VPN tunnel interface for the file server's network. Without this route, the branch router may be dropping the packets or sending them out the wrong interface.

Answer

B) Check the DNS resolution for the file server

Answer

C) Check the VPN encryption settings

Answer

D) Check the file server's antivirus software

Question 6

A network administrator is deploying a wireless network in a warehouse environment with many metal racks. Clients using 802.11ac report strong signal strength but very low throughput. What is the most likely cause?

Accepted Answer

Multipath interference caused by signal reflections off metal surfaces. In a warehouse with many metal racks, 802.11ac signals reflect off the metal surfaces, creating multiple signal paths that arrive at the receiver at slightly different times. This multipath interference causes phase cancellation and intersymbol interference, which degrades the signal-to-noise ratio and forces the use of lower modulation and coding schemes (MCS), drastically reducing throughput despite strong RSSI.

Answer

Co-channel interference from neighboring access points

Answer

The encryption method is set to WEP, which limits throughput

Answer

Too many clients are connected to the same access point

Question 7

A network technician is explaining the function of a default gateway to a junior technician. Which of the following best describes the purpose of a default gateway?

Accepted Answer

It routes traffic from the local network to external networks.. The default gateway is a router or Layer 3 device that serves as the next-hop destination for packets destined to IP addresses outside the local subnet. When a host determines that the destination IP is not on the same network, it forwards the frame to the default gateway's MAC address, which then routes the packet toward the external network. This is defined in RFC 1122 and is essential for any host that needs to communicate beyond its directly connected segment.

Answer

It connects two different VLANs.

Answer

It provides DHCP services to the local network.

Answer

It translates private IP addresses to public IP addresses.

Question 8

A user's computer obtains an IP address from DHCP, can ping the default gateway, but cannot access any external websites. The technician runs 'tracert 8.8.8.8' from the user's computer. The first hop shows the default gateway with low latency, but the second hop shows a timeout. What is the most likely cause?

Accepted Answer

The router's default route pointing to the ISP is missing or incorrectly configured.. The traceroute shows that the user's computer can reach the default gateway (first hop) but times out at the second hop, which is the ISP's router. This indicates that the local router does not have a valid default route pointing to the ISP, so it cannot forward traffic beyond the local subnet. Without a correct default route, packets destined for external networks (like 8.8.8.8) are dropped, even though the user's computer can ping the gateway and obtain an IP via DHCP.

Answer

The user's computer firewall is blocking outbound web traffic.

Answer

The DNS server is not resolving domain names.

Answer

The ISP's DNS server is unreachable.

Question 9

A network technician is troubleshooting a router that is not forwarding packets to a remote destination network. The routing table shows a valid route learned via OSPF. The technician can successfully ping the next-hop IP address from the router. However, packets to the destination network are not being forwarded. Which of the following is the MOST likely cause?

Accepted Answer

Hardware switching/forwarding is disabled or the forwarding table is corrupted. When a router has a valid OSPF-learned route and can ping the next-hop IP but still fails to forward packets, the issue is often with the data plane rather than the control plane. Hardware switching mechanisms (such as fast switching or generic forwarding engines) handle packet forwarding; if they are disabled or the forwarding information base (FIB) becomes corrupted, the router will not forward packets even though the routing table (RIB) is correct. Disabling hardware switching forces the router to use process switching, which can also cause forwarding failures.

Answer

The OSPF neighbor relationship is in the EXSTART state

Answer

The outbound interface has been administratively shut down

Answer

There is an ACL blocking the return traffic

Question 10

A user reports that they can access internal websites but cannot access any external websites. Other users in the same subnet can access external sites. The user's IP configuration shows a correct IP, subnet mask, and default gateway. What is the most likely cause?

Accepted Answer

The proxy server settings are incorrect.. The user can access internal websites but not external ones, while other users in the same subnet have no issues. This points to a client-specific configuration problem rather than a network-wide issue. Incorrect proxy server settings on the user's machine can prevent external HTTP/HTTPS traffic from being routed correctly, even though internal traffic (which may bypass the proxy) works fine.

Answer

The DNS server is not reachable.

Answer

The default gateway is misconfigured.

Answer

The web browser has a corrupted cache.

Question 11

A user reports that they cannot access the company's internal web application at https://apps.internal.company.com. The technician can ping the server's IP address (10.10.10.20) successfully and also successfully telnet to 10.10.10.20 on port 443. However, the web browser displays 'Unable to connect'. What is the most likely cause?

Accepted Answer

The browser is configured to use an incorrect proxy server. The technician can ping the server IP and telnet to port 443, proving the server is reachable and the HTTPS service is listening. However, the browser fails to load the page, which points to a client-side issue. An incorrect proxy server configuration in the browser would cause the browser to send requests to a proxy that cannot reach the internal server, resulting in 'Unable to connect' despite successful network-level connectivity tests.

Answer

The web server service is stopped

Answer

DNS resolution is failing for the FQDN

Answer

A firewall is blocking TCP port 443

Question 12

A user reports that they can access internal resources such as file shares and printers by name, but they cannot access any external websites. The technician checks the IP configuration and finds the workstation has a valid IP address, subnet mask, default gateway, and DNS server addresses. The technician can successfully ping the default gateway and an external IP address like 8.8.8.8. Which of the following should the technician check NEXT?

Accepted Answer

Verify that the DNS server can resolve external domain names.. The user can access internal resources by name and can ping an external IP address (8.8.8.8), which confirms that IP routing, the default gateway, and basic network connectivity are working. The inability to access external websites by name, despite having DNS server addresses configured, points directly to a DNS resolution failure for external domains. Therefore, the next logical step is to verify that the configured DNS server can resolve external domain names, such as by using `nslookup` or `dig` to query a public domain like google.com.

Answer

Perform a traceroute to the external website to identify the point of failure.

Answer

Check the Windows Firewall on the workstation to ensure it is not blocking outbound HTTP traffic.

Answer

Renew the DHCP lease on the workstation.

Question 13

An NOC technician observes that the CPU usage on a core switch has been consistently above 90% for the past hour. Which SNMP operation should the technician use to monitor the CPU load over time with minimal network overhead?

Accepted Answer

SNMP TRAP. D is correct because SNMP TRAP is an unsolicited notification sent from the agent (the switch) to the NMS, which allows the NOC to receive CPU load alerts only when a threshold is exceeded, minimizing network overhead by avoiding continuous polling. In this scenario, the technician wants to monitor CPU load over time with minimal overhead, and traps provide event-driven reporting rather than periodic requests, reducing bandwidth and processing load on both the switch and the network.

Answer

SNMP GET

Answer

SNMP GETNEXT

Answer

SNMP WALK

Question 14

A security administrator is configuring a firewall to allow remote employees to access the company's internal web server (port 443) from the internet. The web server has an internal IP address of 10.0.0.5. The firewall has a public IP of 203.0.113.10. Which type of firewall rule should be created?

Accepted Answer

A) Port forwarding (DNAT) rule. A port forwarding (DNAT) rule is required because the web server uses a private RFC 1918 IP address (10.0.0.5), which is not routable on the public internet. The firewall must translate the destination IP from its public address (203.0.113.10) to the internal server's private address, allowing inbound traffic on port 443 to reach the correct internal host.

Answer

B) Allow rule with source any, destination 10.0.0.5, port 443

Answer

C) Access control list on the internal interface

Answer

D) VPN rule to require remote access VPN

Question 15

A network administrator wants to ensure that only a specific laptop can connect to a particular switch port. The laptop's MAC address is known. Which security feature should be configured?

Accepted Answer

Port security. Port security is the correct feature because it allows the administrator to statically configure the allowed MAC address on a specific switch port. Once configured, the switch will only forward traffic from that MAC address, dropping frames from any other source MAC. This directly fulfills the requirement to restrict access to a single known laptop.

Answer

802.1X

Answer

DHCP snooping

Answer

BPDU guard