CCST Subnetting and CIDR Notation

Question 1

What does CIDR stand for in networking?

Accepted Answer

Classless Inter-Domain Routing

Answer

CIDR stands for Classless Inter-Domain Routing, a method for allocating IP addresses and routing that replaced the older classful network system.

Question 2

Which subnet mask corresponds to the /24 prefix length in CIDR notation?

Accepted Answer

255.255.255.0

Answer

A /24 prefix means 24 bits are set to 1 in the subnet mask, which equals 255.255.255.0 in dotted-decimal notation.

Question 3

How many usable host addresses are available in a /27 subnet?

Accepted Answer

30

Answer

A /27 subnet has 5 host bits (32-27=5), giving 2^5=32 total addresses minus 2 (network and broadcast) = 30 usable hosts.

Question 4

What is the network address for the host 192.168.10.35/28?

Accepted Answer

192.168.10.32

Answer

A /28 mask (255.255.255.240) has a block size of 16; the subnets are .0, .16, .32, .48 — host .35 falls in the .32 subnet.

Question 5

Which class of IPv4 addresses uses the default subnet mask of 255.255.0.0?

Accepted Answer

Class B

Answer

Class B addresses (128.0.0.0–191.255.255.255) use a default subnet mask of 255.255.0.0, providing a /16 prefix.

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