Answer to Question #318955 in Computer Networks for Tom

Question

Find the first address, last address and the number of addresses of a network whose one of the IP addresses is 72.250.220.112 / 27.

Answer 1

The number of addresses is determined as follows:

$2^h-2$ , where $h=32-27=5$;

$2^5-2=30$

Let's find the first address.

Our IP address in binary form:

01001000.11111010.11011100.01110000

Mask in binary form:

11111111.11111111.11100000.00000000

To find the first address we should multiply the IP address by the Mask and add 1 to the last octet.

The first address:

01001000.11111010.11011100.01100001 or 72.250.220.97

The last address:

01001000.11111010.11011100.01111110 or 72.250.223.126

Answer:

The number of addresses:30;

the first address: 72.250.220.97;

the last address: 72.250.223.126.