220-1101 Networking Practice Test 3 — 15 Questions

Question 1

A network technician is configuring a small office network with one router and one managed switch. The network has two VLANs: VLAN 10 (Sales) and VLAN 20 (Engineering). Both VLANs need internet access, and inter-VLAN routing is not required. The technician configures the router's single physical interface with IP 192.168.1.1/24 and creates subinterfaces for VLAN 10 (192.168.10.1/24) and VLAN 20 (192.168.20.1/24). The switch port connecting to the router is configured as an access port in VLAN 10. Which of the following is the MOST likely result?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Neither VLAN can access the internet.. The router's subinterfaces are configured for VLAN 10 and VLAN 20, but the switch port connecting to the router is an access port in VLAN 10. Access ports carry only untagged traffic and drop tagged frames. Therefore, frames sent by the router's subinterfaces (which are tagged with VLAN 10 or 20) will be dropped by the switch. Conversely, frames sent by hosts in either VLAN arrive at the router untagged, so they are associated with the physical interface (192.168.1.1/24), not the subinterfaces (192.168.10.1 or 192.168.20.1). Consequently, neither VLAN can communicate with the router's subinterface IPs, and neither VLAN can access the internet.

Answer

Only VLAN 10 can access the internet; VLAN 20 cannot.

Answer

Both VLANs can access the internet.

Answer

Only VLAN 20 can access the internet; VLAN 10 cannot.

Question 2

A small office recently installed 12 new VoIP phones. Each phone is connected via an Ethernet cable to a 24-port managed PoE+ switch. The switch is powered on, and the network cables are properly terminated. However, none of the VoIP phones power on. The switch's power LED is solid, but the port LEDs remain off. Which of the following is the MOST likely cause?

Accepted Answer

The switch's PoE power budget has been exceeded. The switch's power LED is solid, indicating it has power, but the port LEDs are off, meaning no devices are being powered. Since all 12 VoIP phones are connected to a 24-port PoE+ switch, the most likely cause is that the total power draw of 12 phones exceeds the switch's PoE power budget. PoE+ (802.3at) provides up to 30W per port, but the switch has a limited total power supply (e.g., 250W), and 12 phones at 15-30W each could easily exceed that budget, causing the switch to deny power to all ports.

Answer

The switch ports are configured as access ports for a specific VLAN

Answer

The Ethernet cables are only Category 5 (Cat5)

Answer

The phones require a higher voltage than PoE+ provides

Question 3

A network technician configures a managed switch with two VLANs: VLAN 10 (Marketing: 192.168.10.0/24) and VLAN 20 (Engineering: 192.168.20.0/24). The switch is connected to a router via a single trunk port. The router has subinterfaces configured: G0/0.10 with IP 192.168.10.1/24 and G0/0.20 with IP 192.168.20.1/24. A workstation in Marketing can ping its own default gateway (192.168.10.1) but cannot ping the Engineering gateway (192.168.20.1). Which of the following is the MOST likely cause?

Accepted Answer

The switch port connecting to the router is configured as an access port in VLAN 10. The workstation in Marketing can ping its own gateway (192.168.10.1) because that subnet is directly reachable via the switch. However, it cannot ping the Engineering gateway (192.168.20.1) because the switch port connecting to the router is configured as an access port in VLAN 10. This forces all traffic from the router to the switch to be untagged and only in VLAN 10, so frames destined for VLAN 20 are dropped or misdelivered. A trunk port with 802.1Q encapsulation is required to carry both VLANs over the single link.

Answer

The router's subinterface G0/0.20 is not configured with the correct encapsulation

Answer

The workstation in Marketing has an incorrect subnet mask

Answer

The routing table on the router does not have routes for the Engineering subnet

Question 4

A small office recently installed eight new VoIP phones. Each phone is connected via an Ethernet cable to a 24-port managed PoE+ switch. The switch is powered on, and the network cables are properly terminated. However, none of the VoIP phones power on. The switch's power LED is solid, but the port LEDs for the connected phones remain off. The technician verifies that the PoE budget of the switch (240W) is sufficient for all eight phones (each requiring 6.5W). Which of the following is the MOST likely cause?

Accepted Answer

PoE is disabled on the switch ports or globally.. The most likely cause is that PoE is disabled on the switch ports or globally. Even though the switch supports PoE+ and has sufficient power budget, PoE may be administratively disabled per port or globally (e.g., via the 'power inline never' command on Cisco switches). The solid power LED indicates the switch is powered, but the off port LEDs show no power is being delivered to the phones, which is consistent with PoE being administratively disabled.

Answer

The Ethernet cables are not PoE-compatible.

Answer

The VLAN configuration on the switch is preventing the phones from receiving power.

Answer

The switch's power supply cannot supply enough total wattage.

Question 5

A user reports that they cannot access any websites through their web browser, but they can access shared files on the local network and can successfully ping 8.8.8.8 from the command prompt. The technician checks the IP configuration and finds the workstation has a valid IP address, subnet mask, and default gateway. The DNS server is set to 8.8.8.8. Which of the following is the MOST likely cause of the issue?

Accepted Answer

The web browser proxy settings are configured incorrectly, preventing internet access. The user can ping 8.8.8.8, confirming IP connectivity to a public address, and can access local shares, confirming LAN connectivity. However, a ping to an IP does not test DNS resolution, as no hostname is resolved. The DNS server is set to 8.8.8.8, but being able to ping it does not guarantee that DNS queries succeed. The most likely cause of the browser being unable to load websites while other network functions work is incorrect proxy settings in the web browser. If the browser is configured to use a proxy server that is unreachable or misconfigured, all web requests fail, while applications that do not use the browser's proxy (e.g., ping, file sharing) continue to operate normally. A firewall rule blocking ports 80 and 443 could also cause this, but it is less likely when only one workstation is affected and would not explain why the browser specifically fails while other network utilities work. Therefore, B is the most likely answer.

Answer

A firewall rule is blocking all outbound traffic on ports 80 and 443

Answer

The DNS suffix search order is misconfigured

Answer

The ARP cache is corrupted, preventing the workstation from communicating with the default gateway

Question 6

A small office uses a single router with DHCP enabled for 50 devices. Recently, some devices cannot obtain an IP address, while others work fine. The technician checks the DHCP lease table and sees that it is nearly full with 49 active leases. The network uses a default Class C subnet (255.255.255.0). Which of the following is the MOST appropriate solution to ensure all devices can obtain an IP address in the future?

Accepted Answer

Increase the DHCP scope size by changing the subnet mask to /23 (255.255.254.0).. The default Class C subnet mask /24 (255.255.255.0) provides 254 usable IP addresses, but the DHCP pool is often configured as a smaller range (e.g., 192.168.1.100–192.168.1.199). With 49 active leases out of a typical default pool of 50–100 addresses, the pool is nearly exhausted. Changing the subnet mask to /23 (255.255.254.0) expands the network to 510 usable addresses, allowing the DHCP pool to be enlarged and ensuring all 50 devices can obtain IP addresses without exhausting the pool.

Answer

Change the router's LAN IP address to a different private subnet, such as 10.0.0.1/8.

Answer

Reduce the DHCP lease time so that addresses are recycled more frequently.

Answer

Disable DHCP on the router and assign static IP addresses to all devices.

Question 7

A user reports that their workstation cannot access the internet or any network resources. The technician runs ipconfig and sees the IP address 169.254.10.55 with subnet mask 255.255.0.0. The Ethernet link lights are solid on both the NIC and the switch port. Which of the following is the MOST likely cause?

Accepted Answer

DHCP server is unavailable. The IP address 169.254.10.55 with subnet mask 255.255.0.0 is an Automatic Private IP Addressing (APIPA) address, assigned by Windows when a DHCP server is unavailable. Since the link lights are solid, the physical layer is functional, but the workstation cannot obtain a valid IP address, indicating the most likely cause is a DHCP server failure or misconfiguration.

Answer

The DNS server is unreachable

Answer

The default gateway is misconfigured

Answer

The network cable is faulty

Question 8

A technician is setting up a small office network with a managed switch, a router (192.168.1.1/24), and 20 workstations. All workstations are connected to the switch and configured with static IPs in the range 192.168.1.2-192.168.1.21, subnet mask 255.255.255.0, default gateway 192.168.1.1. All workstations can ping the router successfully, but some workstations cannot ping each other. Which of the following is the MOST likely cause?

Accepted Answer

The managed switch has VLANs configured that isolate some workstation ports.. The most likely cause is that the managed switch has VLANs configured, separating workstations into different broadcast domains. Even though all workstations are on the same IP subnet (192.168.1.0/24), if they are assigned to different VLANs, the switch will not forward frames between them unless a router or Layer 3 switch is configured for inter-VLAN routing. Since the workstations can reach the router (which may be on a trunk or access port in a specific VLAN), but not each other, this points to VLAN segmentation as the root cause.

Answer

Some workstations have duplicate IP addresses.

Answer

The switch has port security enabled, blocking some MAC addresses.

Answer

Incorrect default gateway is configured on some workstations.

Question 9

A technician is adding a wireless access point (AP) in an outbuilding connected via Ethernet to the main office network (192.168.1.0/24). After configuring the AP with a static IP of 192.168.1.250, clients can connect to Wi-Fi but cannot access the internet. The main office devices have no issues. What is the most likely cause?

Accepted Answer

The new AP has its DHCP server enabled. The most likely cause is that the new AP has its DHCP server enabled. When the AP assigns IP addresses to clients via its own DHCP, those clients receive an IP address from a different subnet or scope than the main office network (192.168.1.0/24). This prevents them from reaching the default gateway (e.g., 192.168.1.1) and thus the internet, while the AP itself remains reachable on its static IP. Disabling the AP's DHCP server and allowing clients to obtain addresses from the main network's DHCP server resolves the issue.

Answer

The SSID on the new AP differs from the main network's SSID

Answer

The Ethernet cable connecting the AP is a crossover cable

Answer

The switch feeding the AP is not configured for VLAN 1

Question 10

A small office has a DHCP server that assigns IP addresses in the range 192.168.1.100 to 192.168.1.200. A file server needs a static IP address of 192.168.1.10. Which method should the technician use to ensure the server always receives that IP address without manually configuring the network adapter on the server?

Accepted Answer

Create a DHCP reservation on the router for the server's MAC address. A DHCP reservation binds a specific IP address to a client's MAC address on the DHCP server (often integrated into the router). This ensures the file server always receives 192.168.1.10 from the DHCP server without requiring manual configuration on the server itself, which is the requirement in the question. The reservation works because the DHCP server checks the MAC address in the DHCP request and always offers the reserved IP.

Answer

Configure the server with a static IP address of 192.168.1.10 in the operating system settings

Answer

Change the DHCP range to 192.168.1.11-200 so that .10 is excluded

Answer

Set up a port forwarding rule for the server

Question 11

A company has a router with four Ethernet ports. They need to connect 12 wired devices in the same LAN segment. All devices must receive IP addresses from the same DHCP server running on the router. Which device should the technician add?

Accepted Answer

Switch. A switch is the correct device because it operates at Layer 2 of the OSI model, forwarding Ethernet frames based on MAC addresses, and can connect multiple devices while keeping them in the same broadcast domain. With four router ports already in use, adding a switch allows the 12 wired devices to share a single LAN segment and receive IP addresses from the router's DHCP server, as the switch transparently forwards DHCP broadcast traffic.

Answer

Hub

Answer

Access point

Answer

Modem

Question 12

A technician installs a new VoIP phone that receives power via PoE from a managed switch. The phone powers on but cannot register with the call server. A PC connected to the phone's passthrough port obtains an IP address and accesses the internet normally. Which of the following is the most likely cause of the phone's failure?

Accepted Answer

The switch port has a VLAN mismatch for the voice VLAN. The phone powers on via PoE and the PC behind it works, proving Layer 1 and basic Layer 2 connectivity are fine. The phone cannot register with the call server, which typically requires it to be on the correct voice VLAN. A VLAN mismatch for the voice VLAN means the switch port is configured to tag voice traffic with a different VLAN ID than the phone expects, preventing the phone from communicating with the call server.

Answer

The switch port is configured with a voice VLAN that the phone is not using

Answer

The Ethernet cable between the switch and the phone is faulty

Answer

The phone's MAC address is filtered on the network

Question 13

A network technician is troubleshooting a connectivity issue in a small office. A user's computer obtains an IP address starting with 169.254.x.x. The network uses DHCP from a router with IP 192.168.1.1. The technician checks the cable and sees the link light is on. The computer was working yesterday. Which of the following is the most likely cause?

Accepted Answer

The DHCP server has exhausted its IP pool. The 169.254.x.x address is an Automatic Private IP Addressing (APIPA) address, assigned by Windows when DHCP fails. Since the computer worked yesterday and the link light is on, the most likely cause is that the DHCP server's IP pool is exhausted, preventing new leases. This is a common scenario in small offices with limited IP ranges.

Answer

The DHCP server's IP address changed

Answer

The network cable is a crossover cable

Answer

The computer's network adapter is faulty

Question 14

A technician is replacing a 10/100 Mbps network switch with a new Gigabit switch. After connecting all devices, the technician notices that the link LEDs on several ports are showing amber instead of green. The switch documentation states that green indicates a 1000 Mbps link, and amber indicates a 10/100 Mbps link. All connected devices support Gigabit Ethernet. Which of the following is the MOST likely cause of this issue?

Accepted Answer

The Ethernet cables between the switch and devices are faulty or of poor quality.. The amber link LED indicates that the switch is operating at 10/100 Mbps rather than the expected 1000 Mbps. Since all connected devices support Gigabit Ethernet, the most likely cause is that the Ethernet cables are faulty or of poor quality, as Gigabit Ethernet requires all four twisted pairs (8 wires) to be fully functional, whereas 10/100 Mbps only uses two pairs. A marginal or damaged cable can cause auto-negotiation to fall back to a lower speed.

Answer

The devices are configured for half-duplex, causing auto-negotiation to fail.

Answer

The power supply of the switch is insufficient for all ports.

Answer

The switch is not properly configured for Gigabit mode.

Question 15

A user reports that their laptop can see the company's Wi-Fi SSID but cannot connect to the network. Other users in the same area can connect without issues. The technician verifies that the laptop's wireless adapter is enabled and that the wireless security key is correct. Which of the following should the technician check NEXT?

Accepted Answer

MAC filtering settings on the wireless router. Since other users can connect to the same SSID, the DHCP server and wireless channel are not the issue. The laptop can see the SSID and the security key is correct, so authentication is passing, but association is failing. MAC filtering blocks the laptop's MAC address at Layer 2, preventing it from obtaining an IP address even with correct credentials.

Answer

The DHCP server to ensure IP addresses are available

Answer

The DNS server configuration on the laptop

Answer

Wireless channel interference from other devices