50 ccna practice test Practice Questions: Question Bank 2025

A network administrator needs to divide the 192.168.1.0/24 network into 4 equal subnets. What subnet mask should be used?

Which Cisco IOS command would you use to verify the MAC address table on a switch to troubleshoot connectivity issues?

A company wants to implement a first-hop redundancy protocol to provide gateway redundancy for their LAN. The network uses only Cisco devices. Which protocol should be configured for the most efficient use of bandwidth by allowing multiple routers to forward traffic simultaneously?

What is the administrative distance of OSPF?

A network engineer is configuring port security on a switch interface. The requirement is to allow only two specific MAC addresses and to shut down the port if a violation occurs. Which two commands must be configured? (Choose two represented as the BEST complete answer)

An administrator notices that DHCP clients are not receiving IP addresses. The DHCP server is located on a different subnet than the clients. What must be configured on the router interface connected to the client subnet?

A network engineer is troubleshooting an OSPF adjacency issue between two routers. The output of 'show ip ospf neighbor' shows the neighbor stuck in the EXSTART state. What is the most likely cause?

Which REST API authentication method sends credentials with every request and is stateless?

A company is implementing VLANs on their network. After configuring VLANs on a switch, devices in VLAN 10 cannot communicate with devices in VLAN 20. What device is required to enable communication between these VLANs?

An enterprise network uses 802.1X authentication for network access control. A new wireless printer without 802.1X supplicant capabilities needs to be connected. Which feature should be configured on the switch port to allow this device access while maintaining security?

A network administrator needs to configure a Cisco switch to allow multiple VLANs to traverse a single link between two switches. Which trunk encapsulation protocol is the industry standard that should be configured?

An organization is experiencing intermittent connectivity issues. A technician captures the output of 'show interface GigabitEthernet0/1' and notices a high number of CRC errors. What is the most likely cause of this issue?

A company wants to implement a first-hop redundancy protocol (FHRP) that allows load balancing of client traffic across multiple routers simultaneously. Which protocol should they deploy?

What is the primary purpose of the Spanning Tree Protocol (STP) in a switched network?

A network engineer is troubleshooting OSPF neighbor adjacencies. Two routers connected via a point-to-point link are stuck in the EXSTART state. What is the most likely cause?

Which DHCP message does a client send to accept an IP address offer from a DHCP server?

A company requires that only specific MAC addresses can connect to switchports, and if an unauthorized device connects, the port should be automatically disabled. Which security feature should be implemented?

An administrator needs to configure a router interface to obtain its IPv6 address automatically from the local router without requiring a DHCPv6 server. Which IPv6 address configuration method should be used?

Which REST API HTTP method should be used to retrieve information from a network device without making any changes to its configuration?

A network architect is designing a solution for a campus network that requires centralized management, simplified troubleshooting, and the ability to apply consistent policies across all wireless access points. The solution should minimize individual AP configuration. Which WLAN architecture should be recommended?

A network administrator needs to configure a Cisco router to automatically assign IP addresses to devices on the 192.168.10.0/24 network. The router should reserve addresses .1 through .10 for static assignment, and the default gateway should be 192.168.10.1. Which configuration should be applied?

An administrator is troubleshooting connectivity issues and executes the 'show ip interface brief' command on a router. The output shows interface GigabitEthernet0/1 with status 'up' and protocol 'down'. What is the most likely cause of this issue?

Which JSON data structure correctly represents a network device with hostname 'Router1', IP address '10.1.1.1', and two interfaces 'Gi0/0' and 'Gi0/1'?

A company is implementing a security policy that requires all switches to prevent unauthorized DHCP servers on the network. Legitimate DHCP servers are connected to ports Gi0/1 and Gi0/2. Which feature should be configured and how?

What is the maximum number of usable host addresses in a network with the IP address 172.16.50.0/22?

A network engineer is configuring EtherChannel between two switches using LACP. Switch1 is configured with 'channel-group 1 mode active' and Switch2 is configured with 'channel-group 1 mode passive'. What will be the result?

Which REST API HTTP method should be used to retrieve information about a network device's configuration without making any changes?

A network administrator is configuring OSPF on a multi-access network segment with five routers. To optimize OSPF operations and reduce the number of adjacencies, which configuration should be implemented?

A company's switch has the following port security configuration on interface Fa0/5: switchport mode access switchport port-security switchport port-security maximum 2 switchport port-security violation restrict switchport port-security mac-address sticky Currently, two devices with MAC addresses aaaa.aaaa.aaaa and bbbb.bbbb.bbbb are connected and operational. What will happen if a third device with MAC address cccc.cccc.cccc is connected to this port?

An engineer is configuring VLANs on a Cisco switch. After creating VLAN 100 and assigning ports to it, users report they cannot communicate across the VLAN. The 'show vlan brief' command confirms VLAN 100 exists with the correct ports assigned. What is the most likely additional requirement to enable communication?

A network administrator needs to configure a Cisco switch to automatically obtain an IP address for management purposes. Which command should be applied to the management interface?

What is the primary purpose of the SNMP trap mechanism in network management?

A network engineer is troubleshooting connectivity issues and runs the command 'show ip interface brief' on a router. The output shows an interface with status 'up' and protocol 'down'. What does this indicate?

Which Python data structure would be most appropriate for storing the key-value pairs returned from a REST API call that retrieves device configuration in JSON format?

A company has implemented 802.1X authentication on their network switches. A user's device successfully authenticates but should only have access to VLAN 20. Where is the VLAN assignment typically configured in this scenario?

An organization is deploying IPv6 and wants to use Stateless Address Autoconfiguration (SLAAC). The router sends Router Advertisement messages containing a /64 prefix. How does a host generate its complete IPv6 address using SLAAC?

A network administrator needs to ensure that Cisco switches in the network can automatically recover from a spanning-tree topology loop caused by a unidirectional link failure. Which feature should be configured?

Which RESTful API HTTP method should be used when a network automation script needs to replace an entire router configuration resource?

A company is implementing QoS on their network. Voice traffic has been classified and marked with DSCP EF. At which point in the QoS process does marking typically occur?

A network engineer is configuring OSPF and notices that two routers connected via a point-to-point link are stuck in the EXSTART state. The routers have different MTU values configured on their connecting interfaces (1500 on one side, 1400 on the other). What is the most likely cause of this issue?

A network administrator wants to automate the collection of interface statistics from 50 Cisco routers every hour. Which approach is most efficient for this task?

An engineer is troubleshooting a DHCP issue where clients on VLAN 20 cannot obtain IP addresses. The DHCP server is located on a different subnet. Which command should be configured on the Layer 3 switch serving VLAN 20?

A company is implementing a REST API solution to configure their network devices. Which data format is most commonly used with RESTful APIs for network automation?

A network engineer needs to prevent unauthorized devices from connecting to switch ports in a branch office. The solution should automatically authenticate devices and assign them to appropriate VLANs based on their credentials. Which technology should be implemented?

An organization has deployed IPv6 across their network. Users report intermittent connectivity issues. The engineer discovers that some hosts have multiple IPv6 addresses. What is the most likely explanation?

A network administrator is configuring QoS and needs to mark traffic at Layer 2 for prioritization across the LAN. Which field in the Ethernet frame should be used?

An engineer is troubleshooting OSPF adjacency issues between two routers. The output shows that routers are stuck in the EXSTART state. What is the most likely cause?

A company wants to implement a configuration management solution that uses a declarative approach with templates written in YAML. The solution should be agentless and use SSH for communication. Which tool best fits these requirements?

A network designer is planning a campus network with multiple distribution layer switches. The design requires that if a distribution switch fails, access layer switches should automatically discover and connect to an alternate distribution switch without manual intervention. STP is already in use. Which additional technology would best provide this automatic failover capability for device discovery and connectivity?

An enterprise network uses EtherChannel between core switches. After a configuration change, traffic is not load-balancing as expected, with all traffic using only one physical link. The EtherChannel is operational and all links are up. Investigation reveals that 90% of traffic flows are between the same source and destination IP addresses. Which action will most likely improve load balancing?