Question

Consider a classful IPv4 address 200.200.200.200? What is its implied subnet mask? If we take the same address and append the CIDR notation "/27", now what is its subnet mask?

Answer 1

Answer:

a. 255.255.255.0 (class C)

b. 255.255.255.224

Explanation:

Here, we want to give the implied subnet mask of the given classful IPV4 address

We proceed as follows;

Given IPv4 address: 200.200.200.200

Classes

Class A : 0.0.0.0 to 127.255.255.255

Class B: 128.0.0.0 to 191.255.255.255

Class C: 192.0.0.0 to 223.255.255.255

Class D: 224.0.0.0 to 239.255.255.255

so 200.200.200.200 belongs to Class C and it's subnet mask is 255.255.255.0

In CIDR(Classless Inter Domain Routing)

subnet /27 bits means 27 1s and 5 0s. so subnet

i.e 11111111.11111111.11111111.11100000 which in dotted decimal format is 255.255.255.224 .