Assume that our school has a CIDR address space 12823564019

Assume that our school has a CIDR address space 128.235.64.0/19. Which of the following addresses could be host addresses within that space? Of the ones that are not within the space explain why.

A. 128.235.127.254
B. 128.235.65.254
C. 128.235.63.254
D. 128.235.96.1
E. 128.235.73.255
F. 128.234.73.255

Solution

The given address space is: 128.235.64.0/19

To find the netmask and networks as shown below:

Address:   128.235.64.0         = 10000000.11101011.010 00000.00000000
Netmask:   255.255.224.0 = 19   = 11111111.11111111.111 00000.00000000
Network:   128.235.64.0/19      = 10000000.11101011.010 00000.00000000 (Class B)

The minimum host address is:
HostMin:   128.235.64.1       =   10000000.11101011.010 00000.00000001

The maximum host address is:
HostMax:   128.235.95.254     =   10000000.11101011.010 11111.11111110

So here the following addresses are within the ranges of space:

              128.235.65.254

              128.235.73.255

       2. The reaming addresses are not within the range of host address, why because those addresses are not in between the HostMin and        HostMax of the given address:

               128.235.127.254

               128.235.63.254

                128.235.96.1

                128.234.73.255