CCNA Network Infrastructure and Connectivity Practice Test 12 — 15 Questions

Question 1

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

Question 2

Which two statements accurately describe subnet masks in IPv4?

Accepted Answer

It identifies the network-versus-host split in an IPv4 address.. A subnet mask tells the host which part of the IPv4 address refers to the network and which part refers to the host. In plain language, it helps the device determine whether a destination is local or remote. That decision is essential because it affects whether the host uses ARP directly or forwards traffic to the default gateway.

The wrong answers usually attribute unrelated behaviors to the subnet mask, such as encryption or hostname resolution. The two correct answers are the ones that preserve its role in defining local scope and address structure.

Answer

It resolves hostnames into IP addresses.

Answer

It encrypts packets before they leave the host.

Answer

It replaces the need for a default gateway.

Question 3

A host address is 192.168.1.14/29. Which address is the broadcast address for that host’s subnet?

Accepted Answer

192.168.1.15. A /29 uses blocks of 8 addresses. In plain language, the subnets in the last octet move in increments of 8: 0–7, 8–15, 16–23, and so on. Since the host address ends in 14, it belongs to the 8–15 block. In that block, the last address is the broadcast address, so the broadcast is 192.168.1.15.

This is a classic subnetting pattern because it requires you to place the host inside the correct block and then identify the last address in that block rather than guessing based on the host value itself.

Answer

192.168.1.7

Answer

192.168.1.14

Answer

192.168.1.16

Question 4

A host is configured with 172.16.10.62/27. Which address is the broadcast address for that subnet?

Accepted Answer

172.16.10.63. A /27 uses blocks of 32 addresses. In plain language, the last-octet ranges are 0–31, 32–63, 64–95, and so on. Since the host address ends in 62, it belongs to the 32–63 block. The last address in that block is the broadcast address, so the broadcast is 172.16.10.63.

This is a classic subnetting question because it requires you to place the host inside the correct block and then identify the last address in that block rather than guessing based on the host value alone.

Answer

172.16.10.31

Answer

172.16.10.32

Answer

172.16.10.64

Question 5

A subnet must support 30 usable IPv4 host addresses. Which prefix is the smallest that meets the requirement?

Accepted Answer

/27. A /27 is the smallest valid prefix. In plain language, a /27 provides 32 total addresses, and after subtracting the network and broadcast addresses, 30 usable host addresses remain. A /28 would be too small because it provides only 14 usable hosts.

This is a classic minimum-prefix question because it checks whether you can work backward from a host requirement and choose the smallest subnet that fits without over-allocating more space than necessary.

Answer

/28

Answer

/26

Answer

/25

Question 6

Match each basic networking service to its most accurate role.

Accepted Answer

DNS: Converts domain names to IP addresses. DNS converts domain names to IP addresses; DHCP automates IP configuration; NTP synchronizes clocks across devices; Syslog centralizes event and log reporting for monitoring and troubleshooting.

Answer

DNS: Automates IP address assignment to hosts

Answer

DNS: Maps private IP addresses to public IP addresses

Answer

DNS: Resolves IP addresses to MAC addresses

Question 7

A host is configured as 10.10.20.190/26. Which range contains usable host addresses for that subnet?

Accepted Answer

10.10.20.129 to 10.10.20.190. A /26 uses blocks of 64 addresses. In plain language, the ranges are 0–63, 64–127, 128–191, and 192–255. Since the host ends in 190, it belongs to the 128–191 block. In that block, 10.10.20.128 is the network address and 10.10.20.191 is the broadcast address. That leaves 10.10.20.129 through 10.10.20.190 as the usable host range.

This question checks whether you can identify the correct block and then exclude the reserved endpoints properly.

Answer

10.10.20.128 to 10.10.20.191

Answer

10.10.20.130 to 10.10.20.191

Answer

10.10.20.193 to 10.10.20.254

Question 8

What prefix length corresponds to the subnet mask 255.255.255.224?

Accepted Answer

/27. The subnet mask 255.255.255.224 corresponds to /27. In plain language, the first three octets contribute 24 network bits, and 224 in binary is 11100000, which contributes 3 more network bits. That gives a total of 27 network bits.

This is a common prefix-conversion question because it checks whether you can move between dotted-decimal masks and prefix lengths confidently.

Answer

/26

Answer

/28

Answer

/29

Question 9

Match each basic IPv4 concept to its most accurate role.

Accepted Answer

IP address: Unique identifier for a device on an IP network. An IP address uniquely identifies a device on an IP network. A subnet mask separates the network and host portions of an IP address, enabling devices to determine if a destination is local or remote. A default gateway is the router IP that forwards traffic to other networks when the destination is not on the local subnet. A DNS server translates domain names into IP addresses, allowing devices to reach websites by name.

Question 10

A host is configured as 10.20.30.95/27. Which address is the network address of its subnet?

Accepted Answer

10.20.30.64. A /27 uses blocks of 32 addresses. In plain language, the ranges in the last octet are 0–31, 32–63, 64–95, 96–127, and so on. Since the host address ends in 95, it belongs to the 64–95 block. The first address in that block is the network address, which is 10.20.30.64.

This is a classic subnet-boundary question because it tests whether you can identify the containing block and then choose the first address in that block as the network address.

Answer

10.20.30.32

Answer

10.20.30.95

Answer

10.20.30.96

Question 11

A host uses address 192.168.5.126/25. Which address is the broadcast address for its subnet?

Accepted Answer

192.168.5.127. A /25 divides the /24 into two halves: 0–127 and 128–255. In plain language, the host address 192.168.5.126 is in the lower half, which runs from .0 through .127. The last address in that block is the broadcast address, so the broadcast is 192.168.5.127.

This is a classic subnetting question because it checks whether you can identify the correct block and then select the last address in that block as the broadcast address.

Answer

192.168.5.63

Answer

192.168.5.128

Answer

192.168.5.255

Question 12

A host uses the subnet mask 255.255.255.192. How many usable host addresses exist in each subnet?

Accepted Answer

62. The mask 255.255.255.192 corresponds to /26. That leaves 6 host bits, which means each subnet contains 64 total addresses. After excluding the network and broadcast addresses, 62 usable host addresses remain.

This is a standard host-capacity question. The safest approach is to convert the mask to the prefix, determine the total addresses from the number of host bits, and then subtract the two reserved addresses.

Answer

30

Answer

126

Answer

254

Question 13

A host is configured with IP address 192.168.50.94/27. Which subnet contains that host?

Accepted Answer

192.168.50.64/27. A /27 subnet has a block size of 32. In simple terms, the fourth-octet ranges are 0–31, 32–63, 64–95, 96–127, and so on. Because 94 falls inside the 64–95 range, the network address for the host’s subnet is 192.168.50.64/27.

This kind of question tests whether you can move from prefix length to block size and then place the host inside the correct interval. The most common mistake is choosing a nearby boundary like 96 or 32 without calculating the actual block that contains the address.

Answer

192.168.50.32/27

Answer

192.168.50.96/27

Answer

192.168.50.0/27

Question 14

A subnet has the network address 192.168.30.0/26. What is the broadcast address?

Accepted Answer

192.168.30.63. A /26 subnet contains 64 addresses. In plain language, the block that starts at 192.168.30.0 runs through 192.168.30.63. The first address is the network address and the last address is the broadcast address, so the broadcast for this subnet is 192.168.30.63.

This is a standard subnet-boundary calculation. Once the block size is identified, the broadcast address is simply the final address in that block.

Answer

192.168.30.64

Answer

192.168.30.255

Answer

192.168.30.31

Question 15

What prefix length corresponds to the subnet mask 255.255.255.248?

Accepted Answer

/29. The mask 255.255.255.248 corresponds to /29. In practical terms, the first three octets provide 24 network bits, and the value 248 in the last octet is 11111000 in binary, which contributes 5 more network bits. That gives a total prefix length of 29.

This is a standard dotted-decimal to prefix conversion question. It matters because subnetting often requires you to move comfortably between both forms.

Answer

/28

Answer

/30

Answer

/27