Netmask calculation

[yc_2]

Hi,

(1) How to calculate netmask of an IP address?
(2) Is there any free software that perform the function that feed in IP address and output its netmask?

Thanks in advance.

[Warren_9]

try this

http://logi.cc/nw/NetBitCalc.html

[Michael Schulte zur Sur]

Hi,

There are several classes of ip addresses.
The class is determined by the first byte.
Class A = 1-127 netmask 255.0.0.0
Class B = 128-191 netmask 255.255.0.0
Class C = 192-223 netmask 255.255.255.0
..
However you can not calculate the netmask from the ip address. The netmask divides the ip address into the net portion and the host portion. You can divide the ip range still into subnets. So, there is no fix relationship between ip and netmask.

greetings,

Michael

[Tim Nelson]

Try this online subnet netmask calculator

http://www.subnet-calculator.com/