30 Free CCNA Practice Questions

CCNA Practice Questions

1. Question 1.Refer to the exhibit. Which type of route does R1 use to reach host 10.10.13.10/32?

   
   • A.default route
   • B.network route
   • C.host route(correct answer)
   • D.floating static route
   Show answer & explanationHide answer

   Correct answer: C

   host route

   Explanation

   A /32 prefix identifies a single host, making it a host route. Because routers always choose the most specific matching route using the longest prefix match rule, R1 forwards traffic to 10.10.13.10 using the host route instead of a broader network or default route.

2. Question 2.Refer to the exhibit. Which prefix does Router1 use for traffic to Host A?

   
   • A.10.10.10.0/28
   • B.10.10.13.0/25
   • C.10.10.13.144/28
   • D.10.10.13.208/29(correct answer)
   Show answer & explanationHide answer

   Correct answer: D

   10.10.13.208/29

   Explanation

   Routers use the longest prefix match rule when multiple routes match a destination. The prefix 10.10.13.208/29 is more specific than the other matching routes, so Router1 selects it to forward packets to Host A.

3. Question 3.A frame that enters a switch fails the Frame Check Sequence. Which two interface counters are incremented? (Choose two.)

   • A.input errors(correct answer)
   • B.frame
   • C.giants
   • D.CRC(correct answer)
   • E.runts
   Show answer & explanationHide answer

   Correct answer: A, D

   input errors / CRC

   Explanation

   A Frame Check Sequence (FCS) failure indicates that the frame was corrupted during transmission. The switch increments both the CRC counter, which records checksum failures, and the input errors counter because the received frame contains errors.

4. Question 4.How do TCP and UDP differ in the way that they establish a connection between two endpoints?

   • A.TCP uses the three-way handshake, and UDP does not guarantee message delivery.(correct answer)
   • B.TCP uses synchronization packets, and UDP uses acknowledgment packets.
   • C.UDP provides reliable message transfer, and TCP is a connectionless protocol.
   • D.UDP uses SYN, SYN ACK, and FIN bits in the frame header while TCP uses SYN, SYN ACK, and ACK bits.
   Show answer & explanationHide answer

   Correct answer: A

   TCP uses the three-way handshake, and UDP does not guarantee message delivery.

   Explanation

   TCP is a connection-oriented protocol that establishes communication using the three-way handshake (SYN, SYN-ACK, ACK) before data is transmitted. UDP is connectionless and does not establish a session or guarantee reliable delivery.

5. Question 5.Which 802.11 frame type is Association Response?

   • A.management(correct answer)
   • B.protected frame
   • C.action
   • D.control
   Show answer & explanationHide answer

   Correct answer: A

   management

   Explanation

   Association Response is an IEEE 802.11 management frame. Management frames are responsible for discovering networks, authenticating clients, establishing associations, and maintaining wireless connectivity.

6. Question 6.In which way does a spine-and-leaf architecture allow for scalability in a network when additional access ports are required?

   • A.A spine switch and a leaf switch can be added with redundant connections between them.
   • B.A spine switch can be added with at least 40 GB uplinks.
   • C.A leaf switch can be added with connections to every spine switch.(correct answer)
   • D.A leaf switch can be added with a single connection to a core spine switch.
   Show answer & explanationHide answer

   Correct answer: C

   A leaf switch can be added with connections to every spine switch.

   Explanation

   Spine-and-leaf networks scale horizontally by adding additional leaf switches. Each new leaf switch connects to every spine switch, providing consistent latency, equal-cost paths, and additional access ports without redesigning the network.

7. Question 7.What identifies the functionality of virtual machines?

   • A.The hypervisor communicates on Layer 3 without the need for additional resources.
   • B.Each hypervisor supports a single virtual machine and a single software switch.
   • C.The hypervisor virtualizes physical components including CPU, memory, and storage.(correct answer)
   • D.Virtualized servers run efficiently when physically connected to a switch that is separate from the hypervisor.
   Show answer & explanationHide answer

   Correct answer: C

   The hypervisor virtualizes physical components including CPU, memory, and storage.

   Explanation

   A hypervisor abstracts and virtualizes physical hardware resources such as CPU, memory, storage, and networking. This allows multiple independent virtual machines to share the same physical server while operating as separate systems.

8. Question 8.Which command automatically generates an IPv6 address from a specified IPv6 prefix and MAC address of an interface?

   • A.ipv6 address dhcp
   • B.ipv6 address 2001:DB8:5:112::/64 eui-64
   • C.ipv6 address autoconfig(correct answer)
   • D.ipv6 address 2001:DB8:5:112::2/64 link-local
   Show answer & explanationHide answer

   Correct answer: C

   ipv6 address autoconfig

   Explanation

   The command 'ipv6 address autoconfig' enables Stateless Address Autoconfiguration (SLAAC). The interface automatically builds its IPv6 address from the advertised network prefix and an interface identifier, typically derived from the MAC address or generated randomly.

9. Question 9.When configuring IPv6 on an interface, which two IPv6 multicast groups are joined? (Choose two.)

   • A.2000::/3
   • B.2002::5
   • C.FC00::/7
   • D.FF02::1(correct answer)
   • E.FF02::2(correct answer)
   Show answer & explanationHide answer

   Correct answer: D, E

   FF02::1 / FF02::2

   Explanation

   IPv6-enabled interfaces automatically join the All-Nodes multicast group (FF02::1). Devices operating as routers also join the All-Routers multicast group (FF02::2), which is used for router discovery and routing protocols.

10. Question 10.What is the default behavior of a Layer 2 switch when a frame with an unknown destination MAC address is received?

    • A.The Layer 2 switch forwards the packet and adds the destination MAC address to its MAC address table.
    • B.The Layer 2 switch sends a copy of a packet to CPU for destination MAC address learning.
    • C.The Layer 2 switch floods packets to all ports except the receiving port in the given VLAN.(correct answer)
    • D.The Layer 2 switch drops the received frame.
    Show answer & explanationHide answer

    Correct answer: C

    The Layer 2 switch floods packets to all ports except the receiving port in the given VLAN.

    Explanation

    When the destination MAC address is not present in the MAC address table, the switch performs unknown unicast flooding. The frame is forwarded out every port in the same VLAN except the port on which it was received.

11. Question 11.An engineer must configure a /30 subnet between two routes. Which usable IP address and subnet mask combination meets this criteria?

    • A.interface e0/0 description to XX-AXXX:XXXXX ip address 10.2.1.3 255.255.255.252
    • B.interface e0/0 description to XX-AXXX:XXXXX ip address 192.168.1.1 255.255.255.248
    • C.interface e0/0 description to XX-AXXX:XXXXX ip address 172.16.1.4 255.255.255.248
    • D.interface e0/0 description to XX-AXXX:XXXXX ip address 209.165.201.2 225.255.255.252(correct answer)
    Show answer & explanationHide answer

    Correct answer: D

    interface e0/0 description to XX-AXXX:XXXXX ip address 209.165.201.2 225.255.255.252

    Explanation

    A /30 subnet uses the subnet mask 255.255.255.252 and provides exactly two usable host addresses, making it suitable for point-to-point router links. The correct configuration matches the required /30 addressing.

12. Question 12.Which network allows devices to communicate without the need to access the Internet?

    • A.172.9.0.0/16
    • B.172.28.0.0/16(correct answer)
    • C.192.0.0.0/8
    • D.209.165.201.0/24
    Show answer & explanationHide answer

    Correct answer: B

    172.28.0.0/16

    Explanation

    172.28.0.0/16 belongs to the RFC 1918 private address block 172.16.0.0/12. Private IPv4 networks are intended for internal communication and are not routable on the public Internet.

13. Question 13.Refer to the exhibit. Which statement explains the configuration error message that is received?

    
    • A.It belongs to a private IP address range.
    • B.The router does not support /28 mask.
    • C.It is a network IP address.
    • D.It is a broadcast IP address.(correct answer)
    Show answer & explanationHide answer

    Correct answer: D

    It is a broadcast IP address.

    Explanation

    The configured address is the broadcast address for the subnet. Broadcast addresses are reserved for sending packets to all hosts on a subnet and cannot be assigned to a router interface.

14. Question 14.Which IPv6 address type provides communication between subnets and cannot route on the Internet?

    • A.link-local
    • B.unique local(correct answer)
    • C.multicast
    • D.global unicast
    Show answer & explanationHide answer

    Correct answer: B

    unique local

    Explanation

    Unique Local Addresses (ULAs), which use the FC00::/7 prefix, are designed for private IPv6 networking. They can be routed within an organization's internal network but are not routable on the public Internet.

15. Question 15.Which IPv6 address block sends packets to a group address rather than a single address?

    • A.2000::/3
    • B.FC00::/7
    • C.FE80::/10
    • D.FF00::/8(correct answer)
    Show answer & explanationHide answer

    Correct answer: D

    FF00::/8

    Explanation

    The FF00::/8 prefix is reserved for IPv6 multicast addresses. Multicast traffic is delivered to a group of devices that have joined the multicast group instead of a single destination.

16. Question 16.What are two reasons that cause late collisions to increment on an Ethernet interface? (Choose two.)

    • A.when Carrier Sense Multiple Access/Collision Detection is used
    • B.when one side of the connection is configured for half-duplex(correct answer)
    • C.when the sending device waits 15 seconds before sending the frame again
    • D.when a collision occurs after the 32nd byte of a frame has been transmitted
    • E.when the cable length limits are exceeded(correct answer)
    Show answer & explanationHide answer

    Correct answer: B, E

    when one side of the connection is configured for half-duplex / when the cable length limits are exceeded

    Explanation

    Late collisions are typically caused by duplex mismatches, such as one device operating in half-duplex while the other uses full-duplex, or by exceeding the maximum Ethernet cable length. Both conditions allow collisions to occur outside the normal collision detection window.

17. Question 17.What is a benefit of using a Cisco Wireless LAN Controller?

    • A.It eliminates the need to configure each access point individually.(correct answer)
    • B.Central AP management requires more complex configurations.
    • C.Unique SSIDs cannot use the same authentication method.
    • D.It supports autonomous and lightweight APs.
    Show answer & explanationHide answer

    Correct answer: A

    It eliminates the need to configure each access point individually.

    Explanation

    A Cisco Wireless LAN Controller (WLC) provides centralized management for lightweight access points. Administrators can configure, monitor, update, and troubleshoot multiple APs from a single interface, eliminating the need to configure each AP individually.

18. Question 18.During a routine inspection, a technician discovered that software that was installed on a computer was secretly collecting data about websites that were visited by users of the computer. Which type of threat is affecting this computer?

    • A.DoS attack
    • B.identity theft
    • C.spyware(correct answer)
    • D.zero-day attack
    Show answer & explanationHide answer

    Correct answer: C

    spyware

    Explanation

    Spyware is malicious software that installs itself on a device and secretly gathers information about the user, such as browsing habits, without consent. A DoS attack floods a target with traffic, identity theft is the outcome of stolen data, and a zero-day exploits an unpatched vulnerability.

19. Question 19.Which term refers to a network that provides secure access to the corporate offices by suppliers, customers and collaborators?

    • A.Internet
    • B.intranet
    • C.extranet(correct answer)
    • D.extendednet
    Show answer & explanationHide answer

    Correct answer: C

    extranet

    Explanation

    An extranet is a controlled extension of an organization's intranet that grants external parties such as suppliers, customers, and partners secure access to selected internal resources. An intranet is internal only, the Internet is public, and 'extendednet' is not a real term.

20. Question 20.A large corporation has modified its network to allow users to access network resources from their personal laptops and smart phones. Which networking trend does this describe?

    • A.cloud computing
    • B.online collaboration
    • C.bring your own device(correct answer)
    • D.video conferencing
    Show answer & explanationHide answer

    Correct answer: C

    bring your own device

    Explanation

    Bring Your Own Device (BYOD) is the trend of allowing employees to use their own personal laptops, tablets, and smartphones to access company network resources. It shifts device ownership to the user while the organization retains control over access and security policy.

21. Question 21.What is an ISP?

    • A.It is a standards body that develops cabling and wiring standards for networking.
    • B.It is a protocol that establishes how computers within a local network communicate.
    • C.It is an organization that enables individuals and businesses to connect to the Internet.(correct answer)
    • D.It is a networking device that combines the functionality of several different networking devices in one.
    Show answer & explanationHide answer

    Correct answer: C

    It is an organization that enables individuals and businesses to connect to the Internet.

    Explanation

    An Internet Service Provider (ISP) is a company that connects individuals and businesses to the Internet, typically providing the last-mile link and transit to the global network. Standards bodies define cabling rules, and multifunction devices combine router, switch, and AP roles.

22. Question 22.An employee at a branch office is creating a quote for a customer. In order to do this, the employee needs to access confidential pricing information from internal servers at the Head Office. What type of network would the employee access?

    • A.an intranet(correct answer)
    • B.the Internet
    • C.an extranet
    • D.a local area network
    Show answer & explanationHide answer

    Correct answer: A

    an intranet

    Explanation

    An intranet is the private internal network of an organization, accessible only to its own employees. Because the pricing information is confidential and hosted on internal Head Office servers, the employee is reaching it over the corporate intranet rather than a public or partner-facing network.

23. Question 23.Which statement describes the use of powerline networking technology?

    • A.New “smart” electrical cabling is used to extend an existing home LAN.
    • B.A home LAN is installed without the use of physical cabling.
    • C.A device connects to an existing home LAN using an adapter and an existing electrical outlet.(correct answer)
    • D.Wireless access points use powerline adapters to distribute data through the home LAN.
    Show answer & explanationHide answer

    Correct answer: C

    A device connects to an existing home LAN using an adapter and an existing electrical outlet.

    Explanation

    Powerline networking carries data over the existing electrical wiring in a building. A powerline adapter is plugged into a standard wall outlet at each location, letting a device join the home LAN without running new network cable and without relying on wireless coverage.

24. Question 24.A networking technician is working on the wireless network at a medical clinic. The technician accidentally sets up the wireless network so that patients can see the medical records data of other patients. Which of the four network characteristics has been violated in this situation?

    • A.fault tolerance
    • B.scalability
    • C.security(correct answer)
    • D.Quality of Service (QoS)
    • E.reliability
    Show answer & explanationHide answer

    Correct answer: C

    security

    Explanation

    Security is the network characteristic that protects data confidentiality and integrity. Exposing one patient's medical records to another patient is a confidentiality breach. Fault tolerance, scalability, and QoS relate to availability, growth, and traffic prioritization, none of which were violated here.

25. Question 25.What two criteria are used to help select a network medium from various network media? (Choose two.)

    • A.the types of data that need to be prioritized
    • B.the cost of the end devices utilized in the network
    • C.the distance the selected medium can successfully carry a signal(correct answer)
    • D.the number of intermediate devices installed in the network
    • E.the environment where the selected medium is to be installed(correct answer)
    Show answer & explanationHide answer

    Correct answer: C, E

    the distance the selected medium can successfully carry a signal / the environment where the selected medium is to be installed

    Explanation

    Media selection depends on how far the medium can reliably carry a signal and the physical environment it must survive, such as electrical interference, temperature, or moisture. Endpoint cost, traffic prioritization, and the number of intermediary devices are separate design considerations.

26. Question 26.What type of network traffic requires QoS?

    • A.email
    • B.on-line purchasing
    • C.video conferencing(correct answer)
    • D.wiki
    Show answer & explanationHide answer

    Correct answer: C

    video conferencing

    Explanation

    Video conferencing is real-time, delay-sensitive traffic, so it requires Quality of Service to guarantee low latency and jitter. Email, online purchasing, and wiki traffic tolerate delay and retransmission without noticeably degrading the user experience, so they do not need QoS treatment.

27. Question 27.A user is implementing security on a small office network. Which two actions would provide the minimum security requirements for this network? (Choose two.)

    • A.implementing a firewall(correct answer)
    • B.installing a wireless network
    • C.installing antivirus software(correct answer)
    • D.implementing an intrusion detection system
    • E.adding a dedicated intrusion prevention device
    Show answer & explanationHide answer

    Correct answer: A, C

    implementing a firewall / installing antivirus software

    Explanation

    The baseline security measures for a small office are a firewall to filter traffic entering and leaving the network, and antivirus software on hosts to block malware. IDS and dedicated IPS appliances are advanced controls typically found in larger enterprise deployments.

28. Question 28.Passwords can be used to restrict access to all or parts of the Cisco IOS. Select the modes and interfaces that can be protected with passwords. (Choose three.)

    • A.VTY interface(correct answer)
    • B.console interface(correct answer)
    • C.Ethernet interface
    • D.boot IOS mode
    • E.privileged EXEC mode(correct answer)
    • F.router configuration mode
    Show answer & explanationHide answer

    Correct answer: A, B, E

    VTY interface / console interface / privileged EXEC mode

    Explanation

    Cisco IOS supports passwords on the console line for local access, the VTY lines for remote Telnet or SSH sessions, and privileged EXEC mode via the enable secret command. Ethernet interfaces, boot mode, and router configuration mode are not password protected.

29. Question 29.Which interface allows remote management of a Layer 2 switch?

    • A.the AUX interface
    • B.the console port interface
    • C.the switch virtual interface(correct answer)
    • D.the first Ethernet port interface
    Show answer & explanationHide answer

    Correct answer: C

    the switch virtual interface

    Explanation

    A switch virtual interface (SVI) is a logical Layer 3 interface that gives a Layer 2 switch an IP address for management. Once the SVI has an address and a default gateway, administrators can reach the switch remotely over Telnet or SSH.

30. Question 30.What function does pressing the Tab key have when entering a command in IOS?

    • A.It aborts the current command and returns to configuration mode.
    • B.It exits configuration mode and returns to user EXEC mode.
    • C.It moves the cursor to the beginning of the next line.
    • D.It completes the remainder of a partially typed word in a command.(correct answer)
    Show answer & explanationHide answer

    Correct answer: D

    It completes the remainder of a partially typed word in a command.

    Explanation

    Pressing Tab in the IOS CLI completes a partially typed command or keyword when enough characters have been entered to make it unique. It saves typing and confirms the correct spelling of the command without executing anything.

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