CompTIA Network+ Networking Concepts Practice Questions

1. A workstation can reach every host on its own subnet, but a router is discarding its packets to a remote network because the router has no matching route for the destination. At which OSI layer is this problem occurring?

Objective 1.1

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Answer: C. Layer 3 - Network

Routers forward packets based on logical (IP) addresses and routing tables, which is Layer 3. Layer 2 handles MAC-based delivery inside the local segment, and that is clearly working because local hosts are reachable.

Checked by Claude Opus 5.5 (high effort) · Oct 14, 2026

2. A company hosts its online store on six identical web servers. It wants incoming HTTPS requests spread across all six, and any server that stops responding should be taken out of rotation automatically. Which device meets these requirements?

Objective 1.2

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Answer: D. Load balancer

A load balancer distributes inbound requests across a server pool and uses health checks to stop sending traffic to failed servers. A forward proxy makes outbound requests on behalf of internal clients; it does not spread inbound traffic across servers.

Checked by Claude Opus 5.5 (high effort) · Oct 14, 2026

3. Which statement best describes the function of the Time to Live (TTL) field in an IPv4 packet header?

Objective 1.2

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Answer: B. It is decremented by each router, and the packet is discarded when it reaches zero, preventing packets from looping forever

Each router decrements the IP TTL by one and drops the packet at zero, usually sending an ICMP Time Exceeded message, so routing loops can't circulate packets endlessly. DNS also uses a value called TTL, but that is a cache lifetime on a record, not a field in the IP header.

Checked by Claude Opus 5.5 (high effort) · Oct 14, 2026

4. A cloud architect places database servers in a private subnet of a virtual private cloud (VPC). The servers must download operating system patches from the internet, but nothing on the internet may initiate a connection to them. What should the architect add?

Objective 1.3

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Answer: A. A NAT gateway in a public subnet, with the private subnet's default route pointing to it

A NAT gateway lets instances in a private subnet start outbound connections and receive the replies, while unsolicited inbound connections are not possible. Giving the servers public IPs with a route to the internet gateway would make them directly reachable from the internet, which breaks the requirement.

Checked by Claude Opus 5.5 (high effort) · Oct 14, 2026

5. A security policy requires that an application's directory queries to the domain controllers be encrypted using LDAP over SSL/TLS. Which port must the firewall allow from the application server to the domain controllers?

Objective 1.4

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Answer: C. TCP 636

LDAPS (LDAP over SSL/TLS) uses TCP 636. Port 389 is standard, unencrypted LDAP, and 3389 is RDP.

Checked by Claude Opus 5.5 (high effort) · Oct 14, 2026

6. A DNS provider advertises the same IP address from data centers on several continents, and each client's queries are routed to whichever site is topologically closest. Which traffic type is this?

Objective 1.4

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Answer: B. Anycast

Anycast assigns one address to many hosts, and routing delivers each packet to the nearest one. Multicast delivers a single stream to every member of a group, not to just one nearest host.

Checked by Claude Opus 5.5 (high effort) · Oct 14, 2026

7. A university needs a 10 Gbps link between two buildings that are 6 km apart. Which transmission medium is the most appropriate?

Objective 1.5

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Answer: C. Single-mode fiber

Single-mode fiber has a narrow core and low dispersion, so 10 Gbps optics (such as 10GBASE-LR) reach about 10 km. Multimode fiber is limited to a few hundred meters at 10 Gbps, and Cat 6a copper tops out at 100 m.

Checked by Claude Opus 5.5 (high effort) · Oct 14, 2026

8. A contractor will pull Ethernet cable through the space above a drop ceiling that also serves as an air-return path for the building's HVAC system. Which type of cable should be specified?

Objective 1.5

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Answer: A. Plenum-rated cable

Plenum-rated jackets produce little smoke and few toxic fumes when they burn, which fire codes require in air-handling spaces. Shielded twisted pair protects against interference but says nothing about fire safety, and STP can still have a non-plenum jacket.

Checked by Claude Opus 5.5 (high effort) · Oct 14, 2026

9. Most traffic in a new data center will be east-west between servers. The architect wants every access switch connected to every core switch so that any two access switches are always the same number of hops apart. Which architecture fits this design?

Objective 1.6

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Answer: D. Spine and leaf

In spine and leaf, each leaf (access) switch connects to every spine switch, so any leaf-to-leaf path is leaf-spine-leaf with predictable latency, ideal for east-west traffic. The three-tier model is built around north-south traffic and can add extra hops between servers in different access blocks.

Checked by Claude Opus 5.5 (high effort) · Oct 14, 2026

10. An administrator must divide 192.168.40.0/24 into the largest possible number of equal-sized subnets, each supporting at least 50 hosts. Which subnet mask should be used?

Objective 1.7

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Answer: B. 255.255.255.192

255.255.255.192 (/26) leaves 6 host bits: 2^6 - 2 = 62 usable hosts, giving four subnets from the /24. The next smaller mask, 255.255.255.224 (/27), allows only 2^5 - 2 = 30 hosts, which is too few.

Checked by Claude Opus 5.5 (high effort) · Oct 14, 2026

11. A host is configured with the address 172.16.45.130/27. What is the broadcast address of the host's subnet?

Objective 1.7

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Answer: D. 172.16.45.159

A /27 mask (255.255.255.224) creates blocks of 32, so .130 falls in the 172.16.45.128-.159 subnet: network .128, usable hosts .129-.158, broadcast .159. 172.16.45.191 would be the broadcast address only if the mask were /26.

Checked by Claude Opus 5.5 (high effort) · Oct 14, 2026

12. An organization has rolled out IPv6-only clients with no IPv4 addresses, but users must still reach a vendor's server that only has an IPv4 address. Which technology allows this?

Objective 1.8

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Answer: A. NAT64

NAT64 (usually paired with DNS64) translates between IPv6 and IPv4 so IPv6-only hosts can talk to IPv4-only servers. Dual stack would also work, but only if the clients had IPv4 addresses as well, which they don't.

Checked by Claude Opus 5.5 (high effort) · Oct 14, 2026

CompTIA Network+ · Domain 1 · 23% of the examNetworking Concepts

1. A workstation can reach every host on its own subnet, but a router is discarding its packets to a remote network because the router has no matching route for the destination. At which OSI layer is this problem occurring?

2. A company hosts its online store on six identical web servers. It wants incoming HTTPS requests spread across all six, and any server that stops responding should be taken out of rotation automatically. Which device meets these requirements?

3. Which statement best describes the function of the Time to Live (TTL) field in an IPv4 packet header?

4. A cloud architect places database servers in a private subnet of a virtual private cloud (VPC). The servers must download operating system patches from the internet, but nothing on the internet may initiate a connection to them. What should the architect add?

5. A security policy requires that an application's directory queries to the domain controllers be encrypted using LDAP over SSL/TLS. Which port must the firewall allow from the application server to the domain controllers?

6. A DNS provider advertises the same IP address from data centers on several continents, and each client's queries are routed to whichever site is topologically closest. Which traffic type is this?

7. A university needs a 10 Gbps link between two buildings that are 6 km apart. Which transmission medium is the most appropriate?

8. A contractor will pull Ethernet cable through the space above a drop ceiling that also serves as an air-return path for the building's HVAC system. Which type of cable should be specified?

9. Most traffic in a new data center will be east-west between servers. The architect wants every access switch connected to every core switch so that any two access switches are always the same number of hops apart. Which architecture fits this design?

10. An administrator must divide 192.168.40.0/24 into the largest possible number of equal-sized subnets, each supporting at least 50 hosts. Which subnet mask should be used?

11. A host is configured with the address 172.16.45.130/27. What is the broadcast address of the host's subnet?

12. An organization has rolled out IPv6-only clients with no IPv4 addresses, but users must still reach a vendor's server that only has an IPv4 address. Which technology allows this?