CCNA Network Infrastructure and Connectivity Practice Test 12 — 15 Questions

Question 1

Match each address-related concept to its most accurate meaning.

Accepted Answer

Subnet mask: Indicates network versus host portions of an IPv4 address. The subnet mask is used to distinguish the network portion from the host portion of an IPv4 address. The default gateway is the next-hop router that forwards traffic destined for off-subnet networks. The broadcast address sends packets to all hosts within the local broadcast domain, while the network address identifies the subnet itself and is the first address in the subnet range.

Question 2

A host is configured as 192.168.100.65/26. What is the valid host range for its subnet?

Accepted Answer

192.168.100.65 to 192.168.100.126. A /26 creates blocks of 64 addresses. In plain language, the subnets in the last octet are 0–63, 64–127, 128–191, and 192–255. Because the host address is 192.168.100.65, it belongs to the 64–127 block. In that block, 192.168.100.64 is the network address and 192.168.100.127 is the broadcast address. That leaves 192.168.100.65 through 192.168.100.126 as the valid host range.

This checks whether you can identify both the subnet boundary and the usable range.

Answer

192.168.100.64 to 192.168.100.127

Answer

192.168.100.1 to 192.168.100.62

Answer

192.168.100.66 to 192.168.100.127

Question 3

A subnet requires 200 usable host addresses. Which prefix is the smallest that meets the requirement?

Accepted Answer

/24. A /24 is the smallest valid choice. In plain language, the subnet needs enough total addresses so that after the network and broadcast addresses are reserved, 200 hosts still remain. A /25 is too small because it provides only 126 usable hosts. A /24 provides 254 usable hosts, which satisfies the requirement while being the next logical prefix size up.

This is a standard host-capacity planning question. The key is to work from usable hosts, not just total addresses, and then choose the smallest prefix that actually works.

Answer

/25

Answer

/26

Answer

/27

Question 4

Which two statements accurately describe the role of a switch MAC address table?

Accepted Answer

It maps learned MAC addresses to switch ports for local forwarding decisions.. A switch MAC address table helps the switch make local forwarding decisions efficiently. In plain language, the switch learns which MAC addresses appear on which ports and then uses that information to send frames only where they need to go instead of flooding every frame everywhere.

The MAC table is not the same thing as a routing table, and it is not used for OSPF neighbor storage or DHCP lease records.

Answer

It stores the best Layer 3 routes to remote networks.

Answer

It contains the router’s OSPF authentication keys.

Answer

It assigns IP addresses to end hosts dynamically.

Question 5

A host with address 10.0.0.130/25 needs to identify its subnet. Which subnet is correct?

Accepted Answer

10.0.0.128/25. A /25 uses blocks of 128 addresses. In plain language, that means the fourth-octet ranges are 0–127 and 128–255. Since the host address ends in 130, it belongs to the upper block, which means the subnet is 10.0.0.128/25.

This kind of question is a staple of subnetting because it tests whether you can identify the correct subnet boundary from the prefix and host address. Once you recognize the /25 split, the answer becomes straightforward.

Answer

10.0.0.0/25

Answer

10.0.0.64/25

Answer

10.0.0.192/25

Question 6

A host is assigned 192.168.10.33/28. Which subnet contains that host?

Accepted Answer

192.168.10.32/28. A /28 subnet uses blocks of 16 addresses. In plain language, the last octet ranges move in increments of 16: 0–15, 16–31, 32–47, 48–63, and so on. Since the host address ends in 33, it belongs to the 32–47 block. That means the containing subnet is 192.168.10.32/28.

This style of subnetting question is common because it tests whether you can identify the correct network boundary quickly. The key is to recognize the block size from the prefix and then place the address inside the correct interval without confusing the host with the network address.

Answer

192.168.10.16/28

Answer

192.168.10.48/28

Answer

192.168.10.0/28

Question 7

Match each common network device or concept to its primary role.

Accepted Answer

Router: routes between networks; Switch: forwards within LAN; Hub: repeats signals; Firewall: filters traffic; AP: provides Wi-Fi; Modem: converts digital to analog for WAN. Router routes between networks; switch forwards within LAN; hub repeats signals; firewall filters traffic; AP provides Wi-Fi; modem converts digital to analog for WAN.

Answer

Router: forwards within LAN; Switch: routes between networks; Hub: filters traffic; Firewall: repeats signals; AP: converts digital to analog; Modem: provides Wi-Fi

Answer

Router: filters traffic; Switch: repeats signals; Hub: routes between networks; Firewall: forwards within LAN; AP: converts digital to analog; Modem: provides Wi-Fi

Answer

Router: provides Wi-Fi; Switch: converts digital to analog; Hub: routes between networks; Firewall: forwards within LAN; AP: filters traffic; Modem: repeats signals

Question 8

A host address is 172.16.8.70/26. What is the network address of its subnet?

Accepted Answer

172.16.8.64. A /26 uses blocks of 64 addresses. In plain language, the fourth-octet subnet ranges are 0–63, 64–127, 128–191, and 192–255. Since the host address ends in 70, it belongs to the 64–127 block. That means the network address of the subnet is 172.16.8.64.

This is a standard subnetting calculation. The key is to identify the correct block based on the prefix and then choose the first address in that block as the network address.

Answer

172.16.8.0

Answer

172.16.8.70

Answer

172.16.8.128

Question 9

A network requires at least 500 usable host addresses in one IPv4 subnet. Which prefix is the smallest that meets the requirement?

Accepted Answer

/23. To support at least 500 usable hosts, the subnet must provide at least 502 total addresses when the network and broadcast addresses are included. In plain language, that means 256 total addresses in a /24 are not enough, so the next larger power-of-two block is required. A /23 provides 512 total addresses and 510 usable host addresses, which satisfies the requirement while remaining the smallest valid option.

This is a classic host-capacity question because it checks whether you can work backward from a required usable host count and choose the smallest prefix that works without wasting more space than necessary.

Answer

/24

Answer

/22

Answer

/25

Question 10

A subnet has the network address 192.168.20.128/26. What is the broadcast address?

Accepted Answer

192.168.20.191. A /26 subnet uses blocks of 64 addresses. In plain language, the block that starts at 192.168.20.128 runs through 192.168.20.191. The first address in that block is the network address, and the last address is the broadcast address. That means the broadcast address is 192.168.20.191.

This is a standard subnetting calculation. Once the block size is identified, the broadcast address is simply the last address in the block.

Answer

192.168.20.159

Answer

192.168.20.192

Answer

192.168.20.255

Question 11

A subnet uses the prefix /22. How many usable host addresses are available?

Accepted Answer

1022. A /22 leaves 10 host bits available. In plain language, that means each subnet contains 2^10, or 1024, total addresses. Two of those are reserved for the network and broadcast addresses in normal IPv4 subnetting, leaving 1022 usable host addresses.

This is a common subnet-capacity calculation. The safest method is to calculate the total address count from the number of host bits and then subtract the two reserved addresses. That leads directly to the correct usable-host value.

Answer

254

Answer

510

Answer

2046

Question 12

A host is configured as 192.168.50.130/25. Which address is the broadcast address for its subnet?

Accepted Answer

192.168.50.255. A /25 divides the /24 into two blocks: 0–127 and 128–255. In plain language, because the host ends in 130, it belongs to the upper half, which starts at 128 and ends at 255. The last address in that block is the broadcast address, so the broadcast is 192.168.50.255.

This is a classic subnetting pattern because it tests whether you can identify not just the subnet, but also the reserved last address in that subnet.

Answer

192.168.50.127

Answer

192.168.50.128

Answer

192.168.50.254

Question 13

A host uses the subnet mask 255.255.254.0. Which prefix length does this represent?

Accepted Answer

/23. The mask 255.255.254.0 represents /23. In plain language, the first two octets are fully network bits, the third octet contributes 7 more network bits because 254 in binary is 11111110, and the last octet contributes none. That totals 23 network bits.

This is a common prefix-conversion question because candidates often memorize the usual masks but hesitate when a non-/24 boundary appears. Recognizing that 255.255.254.0 equals /23 is important for subnetting and local-scope calculations.

Answer

/22

Answer

/24

Answer

/25

Question 14

Which two statements accurately describe a default gateway from a host perspective?

Accepted Answer

It is the next-hop path a host uses for destinations outside the local subnet.. A default gateway is the local router or Layer 3 interface that a host uses for traffic destined beyond its own subnet. In plain language, the host uses the gateway when the destination is not local. The default gateway does not replace the host’s own IP address or subnet mask; it complements them by providing the next-hop path for remote communication.

This is a foundational host-networking concept because many connectivity issues come from misunderstanding what the gateway actually does. The two correct answers are the ones that describe remote-traffic forwarding and the local next-hop role of the gateway.

Answer

It replaces the need for a subnet mask.

Answer

It is the same thing as a DNS server.

Answer

It is used only for ARP broadcasts.

Question 15

A host is configured with 10.10.10.130/25. What is the network address of its subnet?

Accepted Answer

10.10.10.128. A /25 divides the address space into two blocks of 128 addresses. In plain language, the ranges are 0–127 and 128–255. Since the host ends in 130, it belongs to the 128–255 half. That means the network address is 10.10.10.128.

This is a common subnet-boundary question because it tests whether you can map a host address into the correct prefix block quickly and confidently.

Answer

10.10.10.0

Answer

10.10.10.64

Answer

10.10.10.255