CompTIA Network+ Practice Questions: Networking Fundamentals

21 free, exam-style CompTIA Network+ (N10-009) practice questions covering Networking Fundamentals. Each question shows the correct answer and a clear explanation. Ready for the real thing? Take the full timed quiz below.

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Q1. Which protocol operates at layer 4 of the OSI model and provides connection-oriented communication?

Explanation: TCP (Transmission Control Protocol) operates at layer 4 and ensures reliable, connection-oriented data delivery. Learn more.

Q2. What is the purpose of a subnet mask?

Explanation: Subnet masks distinguish between network and host portions of an IP address. Learn more.

Q3. Which protocol resolves IP addresses to MAC addresses?

Explanation: ARP (Address Resolution Protocol) maps IP addresses to physical MAC addresses. Learn more.

Q4. Which device operates at Layer 3 of the OSI model?

Explanation: Routers operate at Layer 3 (Network layer) to route packets between networks. Learn more.

Q5. Which IPv6 address type is equivalent to IPv4's 169.254.0.0/16?

Explanation: IPv6 link-local addresses (fe80::/10) are self-assigned like IPv4 APIPA addresses. Learn more.

Q6. Which network topology provides redundant paths between nodes?

Explanation: Mesh topologies provide multiple paths for fault tolerance. Learn more.

Q7. What does a /28 subnet mask provide?

Explanation: /28 (255.255.255.240) provides 16 total addresses minus 2 (network/broadcast) = 14 usable. Learn more.

Q8. Which IPv6 address notation correctly compresses leading zeros?

Explanation: Leading zeros can be removed, and a single :: can replace consecutive zeros. Learn more.

Q9. What is the purpose of an SLAAC (Stateless Address Autoconfiguration)?

Explanation: SLAAC allows IPv6 hosts to self-configure addresses using router advertisements. Learn more.

Q10. Which network device operates at Layer 2 but can filter based on Layer 3/4 information?

Explanation: Multilayer switches combine Layer 2 switching with Layer 3 routing capabilities. Learn more.

Q11. Which IPv6 address type is used for a single interface on multiple hosts?

Explanation: Anycast addresses deliver packets to the nearest of multiple receivers. Learn more.

Q12. What is the purpose of the ARP table?

Explanation: The ARP (Address Resolution Protocol) table stores mappings between IP addresses and MAC addresses on a local network, enabling devices to communicate over Ethernet. Learn more.

Q13. Which protocol is used for automatic IPv6 address configuration?

Explanation: IPv6 supports both stateful (DHCPv6) and stateless (SLAAC) configuration. Learn more.

Q14. What is the purpose of a default gateway?

Explanation: A default gateway serves as the access point or IP router a computer uses to send information to another network. Without it, systems wouldn’t know how to reach destinations outside the local subnet, such as websites on the internet. Learn more.

Q15. What is the purpose of a network switch?

Explanation: A network switch connects devices within a LAN and forwards data based on MAC addresses. Learn more.

Q16. At which layer of the OSI model do MAC addresses and network switches primarily operate?

Explanation: The Data Link layer (Layer 2) is responsible for physical addressing using MAC addresses, framing data for transmission, and error detection. Network switches operate at this layer to forward frames based on destination MAC addresses within a local network segment. Learn more.

Q17. Which layer of the TCP/IP model is responsible for IP addressing, routing of packets between different networks, and path determination?

Explanation: The Internet Layer in the TCP/IP model (which corresponds to the Network Layer in the OSI model) is responsible for logical addressing (IP addresses), routing packets across different networks using protocols like IP, and determining the best path for data to travel. Learn more.

Q18. Which type of IPv4 address is used to send a packet from a single source to multiple, specifically selected destinations that are part of a defined group?

Explanation: Multicast addressing allows a source to efficiently send a single packet that is delivered to a group of interested receivers (the multicast group). IPv4 multicast addresses are in the Class D range (224.0.0.0 to 239.255.255.255). This is used for applications like IPTV and online gaming. Learn more.

Q19. What does "full-duplex" communication mean in the context of a modern switched Ethernet link?

Explanation: Full-duplex communication allows a network device to send and receive data at the same time on a single network link. This is possible on switched Ethernet links (not hubs) because there are separate transmit and receive paths, eliminating the possibility of collisions on that segment. Learn more.

Q20. What is the standard IPv6 loopback address, used by a host to send packets to itself for testing the TCP/IP stack?

Explanation: The IPv6 loopback address is `::1` (which is the compressed form of `0:0:0:0:0:0:0:1`). It serves the same purpose as the 127.0.0.1 address in IPv4, allowing a host to send network packets to itself for diagnostic and testing purposes. Learn more.

Q21. What is the fundamental difference between network bandwidth and network throughput?

Explanation: Bandwidth refers to the maximum data carrying capacity of a network link, often stated by the technology standard (e.g., a 1 Gbps Ethernet link has a bandwidth of 1 Gbps). Throughput, on the other hand, is the actual rate at which data is successfully transferred over the link, which is often lower than the bandwidth due to factors like network overhead, latency, congestion, packet loss, and protocol inefficiencies. Learn more.

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