220-1101 Networking Practice Test 7 — 15 Questions

Question 1

A small office network has two managed switches, Switch A and Switch B, connected via a trunk link. Switch A has VLAN 10 (192.168.10.0/24) and VLAN 20 (192.168.20.0/24) configured. Switch B has only VLAN 10 configured. A router-on-a-stick is connected to Switch A and performs inter-VLAN routing. A workstation connected to an access port on Switch B in VLAN 10 can ping other devices in VLAN 10 on both switches, but it cannot ping a server in VLAN 20 that is connected to Switch A. The trunk port on Switch B is configured to allow all VLANs. Which of the following is the MOST likely cause of this issue?

Accepted Answer

The trunk port on Switch A is not configured to allow VLAN 20 traffic.. The workstation in VLAN 10 on Switch B can communicate with VLAN 10 devices on both switches, confirming that VLAN 10 is functioning correctly across the trunk. However, it cannot reach the server in VLAN 20 on Switch A. Since the router-on-a-stick is connected to Switch A and the trunk port on Switch B is configured to allow all VLANs, the most likely cause is that the trunk port on Switch A is not configured to allow VLAN 20 traffic. Without VLAN 20 permitted on the Switch A trunk, frames from VLAN 20 (including the server's responses) cannot traverse the link to Switch B, breaking connectivity.

Answer

The router's subinterface for VLAN 20 has an incorrect IP address or subnet mask.

Answer

The workstation's default gateway is set incorrectly.

Answer

The switchport mode on Switch B's trunk port is set to access mode.

Question 2

A small office network uses a single managed switch connected to a router. A workstation is configured with a static IP address of 10.0.0.50/24, default gateway 10.0.0.1, and DNS server 10.0.0.10. The workstation can successfully ping other workstations on the same local subnet, but it cannot ping the default gateway (10.0.0.1) or access the internet. The technician checks the router and finds that the router's interface connected to the switch has IP address 10.0.0.1/24. The switch port connecting the router is configured as an access port on VLAN 1. The workstation's switch port is configured as an access port on VLAN 10. Other workstations on VLAN 10 have the same issue. Which of the following is the MOST likely cause?

Accepted Answer

The router's interface does not have a subinterface configured for VLAN 10. The workstation is on VLAN 10, but the router's interface is configured as a simple access port on VLAN 1 with no subinterface for VLAN 10. Without a subinterface (e.g., 10.0.0.1/24 on VLAN 10) or a separate physical interface, the router has no Layer 3 presence in VLAN 10, so it cannot route traffic from VLAN 10 workstations. This is a classic router-on-a-stick misconfiguration where the router lacks a logical interface for the workstation's VLAN.

Answer

The default gateway IP address is incorrect

Answer

The DNS server is unreachable

Answer

The switch is not trunking to the router

Question 3

A user installs a new third-party security software suite on their Windows workstation. After installation, the user can still access files on the local network and can ping external IP addresses like 8.8.8.8, but cannot browse any websites using a web browser. Other workstations on the same network are unaffected. Which of the following is the MOST likely cause?

Accepted Answer

The security software's firewall is blocking outbound HTTP/HTTPS traffic. The user can ping external IP addresses (e.g., 8.8.8.8) and access local network files, which confirms that IP connectivity, the default gateway, and DNS resolution for local resources are working. However, the inability to browse websites (which use HTTP/HTTPS) while other workstations are unaffected strongly indicates that the new third-party security software's firewall is blocking outbound TCP ports 80 and 443. This is a common behavior of security suites that enable strict outbound filtering by default.

Answer

The DNS server address was changed by the software

Answer

The workstation's default gateway was removed

Answer

The security software corrupted the browser's configuration files

Question 4

A small office network consists of a router (192.168.1.1/24) connected to a managed switch. The switch has all ports configured as access ports on VLAN 1. A workstation obtains an IP address of 192.168.1.50/24 from the DHCP server running on the router. The workstation can successfully ping other workstations in the same subnet but cannot ping the default gateway (192.168.1.1). The router's LAN interface is configured with IP address 10.0.0.1/24. Which of the following is the MOST likely cause?

Accepted Answer

The router's LAN interface is on a different subnet than the workstations.. The router's LAN interface is configured with IP address 10.0.0.1/24, while the workstation has an IP address of 192.168.1.50/24. Since these are on different subnets, the workstation cannot reach the default gateway (192.168.1.1) because that address does not exist on the router's LAN interface. The router will not respond to ARP requests for 192.168.1.1, and the workstation cannot send traffic outside its own subnet without a valid gateway on the same subnet.

Answer

The workstation's default gateway is set incorrectly due to a DHCP scope misconfiguration.

Answer

The switch port the workstation is connected to is in the wrong VLAN.

Answer

The Ethernet cable is faulty.

Question 5

A technician is configuring a small office network with a managed switch and a router that supports inter-VLAN routing. A workstation on VLAN 10 (192.168.10.0/24) can ping other workstations on VLAN 10 but cannot ping a server on VLAN 20 (192.168.20.0/24). The switch has a trunk port connecting to the router, and the trunk is configured to allow VLANs 10 and 20. The workstation's default gateway is set to 192.168.10.1. The server's default gateway is set to 192.168.20.1. Which of the following is the MOST likely cause of the problem?

Accepted Answer

A. The router's subinterface for VLAN 20 is not configured or is incorrectly configured.. The workstation can communicate within VLAN 10 but cannot reach VLAN 20, indicating that inter-VLAN routing is failing. Since the trunk is correctly allowing VLANs 10 and 20, the most likely cause is that the router's subinterface for VLAN 20 (e.g., GigabitEthernet0/0.20) is missing, has an incorrect encapsulation dot1Q 20 command, or lacks an IP address in the 192.168.20.0/24 subnet. Without a properly configured subinterface, the router cannot route traffic to or from VLAN 20.

Answer

B. The workstation's firewall is blocking ICMP echo requests.

Answer

C. The switch port connecting the router is configured as an access port on VLAN 1.

Answer

D. The server's default gateway is set to 192.168.20.254.

Question 6

A technician configures a new workstation with DHCP. Initially, the workstation obtains an IP address of 192.168.1.100/24 with default gateway 192.168.1.1 and can browse the internet. After approximately 30 minutes, the user reports that internet access stops working, but the workstation can still ping other local devices on the same subnet. The technician runs ipconfig and sees that the workstation now has an IP address of 169.254.15.78. Which of the following is the MOST likely cause?

Accepted Answer

The DHCP lease expired and the workstation could not contact the DHCP server to renew it. The workstation initially received a valid DHCP lease (192.168.1.100/24). After 30 minutes, the lease expired, and the workstation failed to renew it from the DHCP server. As a result, Windows Automatic Private IP Addressing (APIPA) assigned a 169.254.x.x address, which allows local subnet communication but not internet access. This matches the symptom of losing internet while retaining local connectivity.

Answer

The DHCP server has run out of available IP addresses in the scope

Answer

The DNS server address provided by DHCP has become invalid

Answer

The switch port the workstation is connected to was moved to a different VLAN without trunking

Question 7

Employees in a small office report that their wired network connections become extremely slow or drop every time the office microwave oven is used. The microwave is located in the breakroom, and the network cables for the cubicles run through the ceiling directly above the breakroom. The cables currently installed are unshielded twisted pair (UTP) Cat5e. The technician has confirmed the microwave is not physically damaging the cables and that the router and switch are not overheating. Which of the following solutions would MOST effectively resolve the intermittent network issues?

Accepted Answer

Replace the UTP Cat5e cables with STP Cat6a cables. The intermittent network slowdowns and drops are caused by electromagnetic interference (EMI) generated by the microwave oven, which radiates strongly in the 2.4 GHz range. UTP Cat5e cables lack shielding and are susceptible to this EMI, especially when running through the ceiling directly above the microwave. Replacing them with STP Cat6a cables provides foil or braided shielding that blocks EMI, preserving signal integrity and resolving the issue.

Answer

Upgrade the network switches to models that support QoS (Quality of Service)

Answer

Install ferrite chokes on both ends of each network cable

Answer

Replace the RJ45 wall jacks with shielded Cat6 jacks

Question 8

A user configures a workstation with a static IP address of 192.168.1.50, subnet mask 255.0.0.0, default gateway 192.168.1.1, and DNS server 8.8.8.8. The workstation can ping other computers on the local network (e.g., 192.168.1.100) but cannot ping the default gateway (192.168.1.1) or access the internet. Other workstations using DHCP on the same network have no issues. Which of the following is the MOST likely cause?

Accepted Answer

The subnet mask is incorrectly set to 255.0.0.0, causing the gateway to be considered a remote host.. The subnet mask 255.0.0.0 is a Class A mask, which means the network portion is only the first octet (192). This causes the workstation to believe that the default gateway 192.168.1.1 is on a different network (since 192.0.0.0/8 vs. 192.168.1.0/24), so it attempts to send packets to the gateway via ARP to a remote host, which fails because there is no router configured for that path. The workstation can still ping local hosts like 192.168.1.100 because they fall within the same /8 network as per the misconfigured mask, but the gateway is treated as off-subnet, breaking all traffic beyond the local link.

Answer

The default gateway IP address is incorrect; it should be 192.168.0.1.

Answer

The DNS server address is incorrect; the workstation should use a local DNS server.

Answer

The static IP address conflicts with another device on the network.

Question 9

A small office network uses a single router configured as a DHCP server for the 192.168.1.0/24 network. The DHCP scope is set to 192.168.1.10 - 192.168.1.50. Over the past week, several workstations have reported intermittent connectivity. The technician checks a workstation and finds that its IP address has changed from 192.168.1.20 to 169.254.15.100. Other workstations also show similar APIPA addresses. The DHCP server logs indicate that many lease requests are being declined. The network has 45 devices that require IP addresses. Which of the following is the MOST likely cause of the issue?

Accepted Answer

The DHCP scope is too small for the number of devices on the network. The DHCP scope is 192.168.1.10–192.168.1.50, which provides only 41 usable addresses. With 45 devices requiring IP addresses, the scope is exhausted. When a DHCP server cannot assign an address, clients self-assign an APIPA address (169.254.x.x) per RFC 3927, explaining the intermittent connectivity and declined lease requests.

Answer

The DHCP server is malfunctioning and needs to be restarted

Answer

The DNS server is not resolving hostnames correctly

Answer

The network switch is flooding the network with broadcast traffic

Question 10

A technician replaced an unmanaged network switch with a new managed switch in a small office. After reconnecting all devices, some workstations can access the internet, but others cannot. The workstations that cannot access the internet are physically connected to the switch and their link lights are on. The technician checks the switch configuration and finds that all ports are set to 'trunk' mode by default. The router is connected to port 1, which is also set to trunk mode. Which of the following is the MOST likely cause?

Accepted Answer

The switch ports that are connected to workstations need to be configured as access ports instead of trunk ports. The default trunk mode on all ports causes the switch to expect 802.1Q-tagged frames from the workstations. Since standard workstations send untagged Ethernet frames, the switch drops or misinterprets them, preventing those devices from communicating with the router. Configuring the workstation ports as access ports allows the switch to accept untagged frames and properly forward them to the trunk link (port 1) to the router.

Answer

The router does not support trunking

Answer

The Ethernet cables are faulty

Answer

The workstations have incorrect IP settings

Question 11

A technician configures a new workstation with a static IP address of 10.0.0.5, subnet mask 255.255.255.0, default gateway 10.0.0.1, and DNS server 8.8.8.8. The workstation can ping the gateway (10.0.0.1) but cannot ping any external IP addresses like 8.8.8.8 or access the internet. Other workstations on the same network using DHCP are working fine. The router's WAN connection is working. Which of the following is the MOST likely cause?

Accepted Answer

The router is not configured with a route back to the 10.0.0.0 network.. The workstation can ping its default gateway (10.0.0.1), confirming that Layer 2 and Layer 3 connectivity to the local router interface is functional. However, it cannot reach external IPs like 8.8.8.8, which indicates that the router is not forwarding packets from the 10.0.0.0/24 subnet to the WAN. Since other DHCP clients work, the router lacks a static route back to this specific subnet, causing return traffic to be dropped.

Answer

The IP address conflicts with another device on the network.

Answer

The default gateway is in a different subnet.

Answer

The DNS server is not reachable.

Question 12

A user can access local network resources but cannot browse the internet. Other users on the same network have no issues. The technician checks the workstation's IP configuration: IP 192.168.1.100, subnet mask 255.255.255.0, default gateway 192.168.1.1, DNS server 192.168.1.1. The workstation successfully pings the default gateway (192.168.1.1). The technician then tries to ping 8.8.8.8 and the ping fails. Which of the following should the technician check NEXT?

Accepted Answer

The routing table on the router. Since the workstation can ping the default gateway (192.168.1.1) but cannot ping 8.8.8.8, the issue is beyond the local subnet. This indicates a routing problem, not a local connectivity or DNS issue. The technician should check the router's routing table to ensure there is a default route (0.0.0.0/0) pointing to the ISP or upstream gateway, as the router may not be forwarding traffic to external networks.

Answer

The switch port configuration

Answer

The DNS server settings

Answer

The DHCP lease expiration

Question 13

A user reports that they cannot access the internet, but they can still access shared folders on the local network. The technician runs ipconfig on the workstation and sees an IP address of 169.254.10.15 with a subnet mask of 255.255.0.0. Which of the following is the MOST likely cause of this issue?

Accepted Answer

The DHCP server is unavailable. The IP address 169.254.10.15 with a subnet mask of 255.255.0.0 is an Automatic Private IP Addressing (APIPA) address, which Windows assigns when a DHCP server is unavailable or fails to respond. Since the user can still access local shared folders (local link-layer communication works), but cannot reach the internet, the core issue is the lack of a valid DHCP lease, not a DNS or gateway misconfiguration.

Answer

The DNS server is not responding

Answer

The default gateway address is incorrect

Answer

The workstation has a static IP address configured

Question 14

A user reports that they cannot access any websites using their web browser, but they can successfully ping external IP addresses such as 8.8.8.8. Other users on the same network are able to browse the internet normally. The technician checks the workstation's IP configuration and finds the following: IP 192.168.1.50, subnet mask 255.255.255.0, default gateway 192.168.1.1, DNS server 192.168.1.1. The technician can ping 192.168.1.1 successfully. Which of the following is the MOST likely cause?

Accepted Answer

DNS server not responding or misconfigured. The user can ping external IP addresses (e.g., 8.8.8.8) and the default gateway (192.168.1.1), confirming that IP routing and the gateway are functional. However, they cannot resolve domain names to IP addresses, which is a classic symptom of DNS failure. Since the DNS server is set to 192.168.1.1 (likely the gateway) and other users on the same network can browse normally, the issue is isolated to this workstation's DNS configuration or the DNS service on that server not responding to this specific client.

Answer

Incorrect subnet mask

Answer

Incorrect default gateway

Answer

Firewall blocking web traffic (port 80/443)

Question 15

A company replaces an unmanaged network switch with a new managed switch in a small office. After reconnecting all devices, some workstations can access the internet, but others cannot. The workstations that cannot access the internet are all connected to ports 1-8 of the new switch, while workstations on ports 9-16 work normally. The router is connected to port 24. The technician checks the switch configuration and finds that all ports are in the default VLAN 1, but ports 1-8 have been accidentally reassigned to VLAN 2. Which of the following is the MOST likely reason the workstations on ports 1-8 cannot access the internet?

Accepted Answer

The workstations on ports 1-8 are on a different VLAN than the router, preventing them from reaching the default gateway.. The router is connected to port 24, which remains in the default VLAN 1. Workstations on ports 1-8 have been reassigned to VLAN 2. Since VLANs create separate broadcast domains, devices in VLAN 2 cannot communicate with the router's interface in VLAN 1 unless a Layer 3 device (like a router or Layer 3 switch) routes between the VLANs. Without inter-VLAN routing configured, the workstations in VLAN 2 cannot reach their default gateway (the router), and thus cannot access the internet.

Answer

The switch needs to be power cycled to apply the VLAN configuration changes.

Answer

The workstations on ports 1-8 have incorrect subnet masks configured.

Answer

The switch ports are not configured as trunk ports for the router connection.