N10-009 Practice Test 7 — 10 Questions

Question 1

Which of the following best describes a broadcast domain?

Accepted Answer

All devices that can receive a broadcast frame from any other device in the network segment. A broadcast domain is defined as the set of all devices that can receive a broadcast frame (destination MAC FF:FF:FF:FF:FF:FF) sent by any other device within the same network segment. This boundary is typically enforced by Layer 3 devices like routers, which do not forward broadcast frames, whereas Layer 2 switches forward broadcasts out all ports except the receiving port within the same VLAN.

Answer

All devices connected to the same switch

Answer

All devices that share the same IP subnet

Answer

All devices that have the same MAC address prefix

Question 2

A user reports intermittent connectivity issues. The technician runs ping tests and notices that pings to the default gateway sometimes fail and sometimes succeed. While pinging, the technician observes that some replies have high latency. Which tool should the technician use to analyze the path and identify where packets are being delayed?

Accepted Answer

traceroute / tracert. Traceroute (tracert on Windows) is the correct tool because it sends packets with incrementing Time-to-Live (TTL) values to map the entire Layer 3 path from source to destination. By measuring the round-trip time (RTT) for each hop, it can pinpoint exactly which router or link is introducing high latency or packet loss, addressing the intermittent connectivity and delayed replies observed in the ping tests.

Answer

nslookup

Answer

ipconfig

Answer

arp

Question 3

A security analyst notices that the network has been flooded with packets that have the same source IP address as the company's internal DNS server. This is likely an example of which type of attack?

Accepted Answer

IP spoofing. IP spoofing is the correct answer because the attacker is forging the source IP address of packets to impersonate the company's internal DNS server. By flooding the network with packets that appear to originate from a trusted internal server, the attacker can bypass security controls, launch reflection attacks, or cause denial of service. This directly matches the scenario where the source IP is falsified to match a legitimate internal host.

Answer

Smurf attack

Answer

Man-in-the-middle

Answer

ARP poisoning

Question 4

A company is implementing a DMZ to host public-facing web and email servers. The DMZ network uses private IP addresses, and the internal network also uses private IP addresses. The company has only one public IP address assigned to the border router's external interface. Which of the following should be configured to allow internet users to access the DMZ servers?

Accepted Answer

Port forwarding to the private IP addresses of the servers.. Port forwarding (often configured as static NAT with a single public IP) allows the border router to forward incoming traffic on specific TCP/UDP ports (e.g., 80 for web, 25 for SMTP) to the private IP addresses of the DMZ servers. Since the company has only one public IP, this is the only way to direct external requests to the correct internal server without requiring multiple public IPs.

Answer

NAT with overload to translate multiple internal addresses to the single public IP.

Answer

Static NAT mapping each DMZ server to a unique public IP.

Answer

A VPN tunnel between the DMZ and the internal network.

Question 5

A network administrator is installing cable in a plenum space (an area used for air circulation, such as above a drop ceiling). Which cable type is required by most building codes for such an installation?

Accepted Answer

Plenum-rated cable. Plenum-rated cable is required by most building codes (e.g., NFPA 70, National Electrical Code) for installation in plenum spaces because it is constructed with fire-retardant materials, such as FEP or PFA, that produce minimal smoke and are self-extinguishing. This prevents toxic fumes and flames from spreading through air-handling areas, ensuring safety in case of a fire. Standard PVC-jacketed cable would release hazardous smoke and support flame propagation, making it illegal in plenum spaces.

Answer

PVC-jacketed cable

Answer

Riser-rated cable

Answer

Low Smoke Zero Halogen (LSZH) cable

Question 6

A user can ping the default gateway (192.168.1.1) but cannot ping the external IP address 8.8.8.8. Other users on the same subnet can ping 8.8.8.8 without issue. The user's IP configuration is correct: IP 192.168.1.10/24, default gateway 192.168.1.1, DNS 8.8.8.8. What is the most likely cause?

Accepted Answer

The computer's firewall is blocking outbound ICMP. The user can ping the default gateway (192.168.1.1) but not the external IP 8.8.8.8, while other users on the same subnet can ping 8.8.8.8 without issue. This isolates the problem to the user's specific host, not the network infrastructure. A local firewall on the user's computer blocking outbound ICMP (Internet Control Message Protocol) traffic would prevent ping to external IPs while still allowing local subnet communication, as ICMP is often restricted by default in some security policies.

Answer

The router is missing a default route to the internet

Answer

The DNS server is not resolving the hostname

Answer

The network cable is loose or faulty

Question 7

A network engineer is troubleshooting intermittent call drops on a VoIP deployment. The network uses separate VLANs for voice (VLAN 20) and data (VLAN 10). Switch ports connecting the IP phones are configured with the correct voice VLAN. Which of the following is the MOST likely cause to check NEXT?

Accepted Answer

Verify that QoS markings and queuing are configured on the switches and routers. Intermittent call drops on a VoIP deployment with separate voice and data VLANs most likely stem from insufficient or misconfigured QoS markings and queuing. Voice traffic is sensitive to latency, jitter, and packet loss, which occur when data traffic competes for bandwidth without proper prioritization. Verifying that switches and routers have consistent QoS policies (e.g., marking with DSCP EF for RTP and queuing with strict priority) is the logical next step after ensuring the voice VLAN is correctly assigned.

Answer

Check the DNS server for the phone's name resolution

Answer

Replace the patch cables from the phones to the switches

Answer

Increase the DHCP lease time for the phones

Question 8

Which of the following is the primary function of a subnet mask in IPv4 networking?

Accepted Answer

It determines the network portion of an IP address. The subnet mask's primary function is to distinguish the network portion from the host portion of an IPv4 address. By applying a bitwise AND operation between the IP address and the subnet mask, the network address is derived, which is essential for routing decisions. Without this separation, devices cannot determine whether a destination is local or requires forwarding through a router.

Answer

It identifies the default gateway for a subnet

Answer

It provides encryption for data in transit

Answer

It maps IP addresses to MAC addresses

Question 9

Users in a branch office report that file transfers to the data center are slow. A technician runs a traceroute and sees consistently high latency on hop 5. The technician then pings hop 5 and gets replies with varying response times. There are no errors reported on the interface. What is the most likely cause?

Accepted Answer

Interface congestion causing queuing delays.. High latency on hop 5 with varying response times and no interface errors indicates that the router at hop 5 is experiencing congestion, causing packets to be queued before transmission. This queuing delay results in increased and variable round-trip times (RTT), which is a classic symptom of interface congestion. The absence of errors rules out physical-layer issues, and the consistent latency on that specific hop points to a bottleneck at that router's egress interface.

Answer

Routing loop causing packets to be dropped.

Answer

DNS server misconfiguration causing lookup delays.

Answer

Firewall inspecting traffic and adding latency.

Question 10

A network administrator scheduled a change window to upgrade the firmware on a core switch. During the upgrade, the switch fails to boot properly. The administrator needs to restore the switch to its previous operational state. Which of the following should the administrator have done before the upgrade to facilitate a successful rollback?

Accepted Answer

Backed up the current configuration and firmware image.. Backing up both the current configuration and the firmware image ensures that the administrator can restore the switch to its exact previous operational state if the upgrade fails. Without a backup of the firmware image, the switch may not have a valid bootable image to revert to, even if the configuration is saved. This is a fundamental prerequisite for any firmware upgrade rollback plan.

Answer

Notified all users of the maintenance window.

Answer

Disconnected all redundant links.

Answer

Set the switch to boot from an alternative image.