220-1201 Network Troubleshooting Practice Test 2 — 15 Questions

Question 1

A user reports that their laptop can connect to the internet via Ethernet but cannot connect to any Wi-Fi networks. The wireless adapter is enabled and shows available networks, but connecting always fails. What is the most likely cause?

Accepted Answer

The wireless security settings are incorrect.. When a device can connect via Ethernet but not Wi-Fi, the issue is usually with the wireless configuration or hardware, not the network itself. Incorrect wireless security settings, such as a mismatched encryption type or password, are a common cause of connection failure after the network is detected.

Answer

The DHCP server is out of IP addresses.

Answer

The wireless adapter driver is corrupted.

Answer

The router’s SSID is hidden.

Question 2

A small office has a single switch connecting all workstations. Several users report that they cannot access the internet, but they can still communicate with each other on the local network. What is the most likely cause?

Accepted Answer

The router is not properly routing traffic to the internet.. Local communication working while internet access fails points to a problem with the router or the connection between the switch and the router. The switch itself is functioning correctly for local traffic, so the issue is upstream.

Answer

The switch has a bad port.

Answer

The DNS server is unreachable.

Answer

The workstations have incorrect subnet masks.

Question 3

During a network upgrade, a new switch is installed. After connecting all devices, one workstation cannot obtain an IP address via DHCP, while all other workstations on the same switch work fine. What is the first step to troubleshoot this issue?

Accepted Answer

Check if the network cable is securely connected and the link lights are on.. When a single workstation fails to get an IP address but others succeed, the problem is likely with that workstation or its cable. Checking the physical connection is the quickest and easiest first step before moving to software or configuration checks.

Answer

Replace the network cable.

Answer

Restart the DHCP service on the router.

Answer

Assign a static IP address to the workstation.

Question 4

A company’s web server is accessible from the internal network but not from the internet. The server has a static IP of 192.168.1.10, and the router’s public IP is 203.0.113.50. What configuration is most likely missing?

Accepted Answer

Port forwarding is not configured on the router.. For a server on a private IP to be accessible from the internet, the router must have port forwarding configured to direct incoming traffic to the server’s private IP. Without it, requests to the public IP are dropped.

Answer

The server’s default gateway is incorrect.

Answer

A firewall rule on the server is blocking inbound traffic.

Answer

The DNS A record for the server points to the wrong IP.

Question 5

A network administrator is troubleshooting intermittent connectivity issues on a fiber optic link between two buildings. The link works but has occasional errors. The technician inspects the fiber and finds that the connectors are dirty. After cleaning them, the issue persists. What should the technician check next?

Accepted Answer

Check the light level with a power meter.. Dirty connectors are a common cause of fiber issues, but if cleaning doesn't resolve it, the next step is to verify the light level using a power meter. This will determine if the signal is strong enough or if there is attenuation from other causes like bends or damaged cables.

Answer

Replace the entire fiber cable.

Answer

Swap the SFP modules on both ends.

Answer

Run a loopback test on the switch ports.

Question 6

A user reports that their laptop's Wi-Fi connection drops every 10 minutes, but reconnects immediately. The technician notices that the laptop is connected to a 5 GHz SSID. What is the most likely cause?

Accepted Answer

The user is at the edge of the 5 GHz coverage area.. 5 GHz signals have shorter range and are more easily obstructed. If the user is at the edge of coverage, the signal may intermittently drop. The periodic nature suggests a weak signal, not interference or driver issues.

Answer

The laptop's Wi-Fi driver is outdated.

Answer

The access point is configured with a short DHCP lease time.

Answer

There is interference from a microwave oven.

Question 7

A small office has a single switch connecting all workstations. Users report that they can see each other on the network but cannot access the internet. The router's link light is off. What should the technician check first?

Accepted Answer

Check the Ethernet cable between the switch and router.. The link light being off indicates a physical layer problem between the switch and router. The most common cause is a faulty or loose cable, so checking the cable connection is the logical first step in network troubleshooting.

Answer

Replace the switch.

Answer

Reboot all workstations.

Answer

Update the router's firmware.

Question 8

During a network upgrade, a technician installs a new 802.11ax (Wi-Fi 6) access point in a conference room. Users now report intermittent disconnections on their older laptops. What is the most likely cause?

Accepted Answer

The channel width is set too wide for older clients.. Wi-Fi 6 access points can operate in mixed mode, but older clients may struggle with channel width or band-steering settings. The most common issue is that the AP is using a channel width (e.g., 160 MHz) that older devices do not support, causing instability.

Answer

The access point is overheating.

Answer

The DNS server is misconfigured.

Answer

The power over Ethernet (PoE) injector is faulty.

Question 9

A customer complains that their desktop computer loses network connectivity every time a large file is transferred. The issue does not occur during normal web browsing. What hardware component is most likely at fault?

Accepted Answer

The network interface card (NIC) is failing.. This is a classic symptom of a failing or overheating network interface card (NIC). High data throughput generates heat, and a marginal NIC may fail under sustained load, while low-bandwidth tasks work fine.

Answer

The CPU is overheating.

Answer

The power supply unit is underpowered.

Answer

The Ethernet cable is too long.

Question 10

A user reports that their laptop can connect to the corporate Wi-Fi but cannot access the internet. Other devices on the same network work fine. What is the most likely cause of this issue?

Accepted Answer

The laptop's DNS server settings are incorrect.. This scenario points to a client-specific configuration problem. Since other devices work, the issue is isolated to the user's laptop, and a misconfigured DNS setting is a common cause for internet access failure while local network connectivity remains intact.

Answer

The wireless router has failed.

Answer

The network cable is unplugged.

Answer

The ISP is down.

Question 11

A technician is troubleshooting a network where a single workstation cannot access any network resources. The link light on the NIC is solid, and the IP configuration shows an address of 192.168.1.100 with a subnet mask of 255.255.255.0. The workstation can ping its own IP but not the default gateway (192.168.1.1). What is the most likely cause?

Accepted Answer

The switch port is configured with the wrong VLAN.. The workstation has a valid IP and can ping itself, indicating the NIC and stack are working. However, it cannot reach the gateway, which suggests a Layer 2 issue—likely an incorrect or missing default gateway configuration, or a VLAN mismatch on the switch port.

Answer

The DNS server is unreachable.

Answer

The Ethernet cable is a crossover cable.

Answer

The workstation's subnet mask is wrong.

Question 12

A technician is troubleshooting a network where a user's PC has an IP address of 169.254.12.34. The PC is connected to a switch that is uplinked to a router with DHCP enabled. What is the most likely cause?

Accepted Answer

The Ethernet cable between the PC and the switch is faulty.. An APIPA address (169.254.x.x) indicates the PC failed to get a DHCP lease. Since the router has DHCP enabled, the issue is likely a bad Ethernet cable or a port problem preventing communication with the DHCP server.

Answer

The DHCP server is out of IP addresses.

Answer

The PC's DNS settings are incorrect.

Answer

The router's firewall is blocking DHCP requests.

Question 13

A company's network uses a 10.0.0.0/8 private IP scheme. A remote user connects via VPN and gets an IP of 172.16.0.5. They can access the internet but cannot reach internal servers at 10.1.1.50. What is the most likely cause?

Accepted Answer

The VPN client is using split tunneling and no route to 10.0.0.0/8 is defined.. The VPN client receives a different subnet (172.16.0.0) than the internal network (10.0.0.0). This is a routing issue—the VPN client's traffic to the internal network may not be routed correctly, or split tunneling is misconfigured. The most common fix is to ensure the VPN routes include the internal subnet.

Answer

The internal server's firewall is blocking the VPN IP range.

Answer

The VPN server's DHCP scope is exhausted.

Answer

The user's DNS server is set to a public DNS like 8.8.8.8.

Question 14

A technician is setting up a new printer on a network. The printer has a static IP address of 192.168.1.50, but users cannot ping it from their workstations. The workstations are on the 192.168.1.0/24 subnet. What should the technician check first?

Accepted Answer

Verify the switch port status and cable connection.. Since the printer and workstations are on the same subnet, the issue is likely at Layer 2 or Layer 1. The first step is to verify the physical connection and link status on the switch port, as a bad cable or disabled port would prevent communication.

Answer

Check the printer's default gateway setting.

Answer

Change the printer's IP address to a DHCP address.

Answer

Reboot the router.

Question 15

A company deploys a new VoIP phone system. Users report that calls are choppy and sometimes drop. The network uses a single flat subnet with no QoS. What is the most likely cause?

Accepted Answer

There is no Quality of Service (QoS) configured.. VoIP traffic is sensitive to latency, jitter, and packet loss. Without QoS, data traffic can congest the network, causing choppy audio and dropped calls. Implementing QoS prioritizes voice traffic.

Answer

The VoIP phones have incorrect DNS settings.

Answer

The switch ports are set to half-duplex.

Answer

The Ethernet cables are Cat5 instead of Cat6.