Is there a tool for subnetting for free?

Question

I'd like a program that I can write in an IP address and give it the Subnet mask and have it divide the networks in C level networks.

Thanks.

Something that I can download please, not a website.

Answer 1

ipcalc has a binary program and a site: ipcalc. I don't know if it has binaries for windows but almost every linux distro has it packaged. The command line tool has a lot of options on how to show and how to calculate the subnet.

EDIT: There's how to run it on windows (it's a perl script)

Answer 2

http://www.subnet-calculator.com/cidr.php is pretty good.

Also, there are no network classes anymore, so a C class network is an antiquated term. You want to divide it into smaller /24 subnets.

Answer 3

You mean like this

Answer 4

Have you looked at Solarwinds Subnet Calculator?

Google will also point you to lots of online calculators.

Answer 5

I wrote one that you give a starting network and mask and then tell it the number of hosts per net and number of nets in your new scheme.

Lets say you start with 172.16.0.0 /12 and tell it you want 10 nets with 254 hosts. Here are the results.

Network           Net Broadcast     CIDR Mask              UsableHosts 
172.16.0.0        172.23.255.255    13   255.248.0.0       524,286     AVL  isPrivate
172.24.0.0        172.27.255.255    14   255.252.0.0       262,142     AVL  isPrivate
172.28.0.0        172.29.255.255    15   255.254.0.0       131,070     AVL  isPrivate
172.30.0.0        172.30.255.255    16   255.255.0.0       65,534      AVL  isPrivate
172.31.0.0        172.31.127.255    17   255.255.128.0     32,766      AVL  isPrivate
172.31.128.0      172.31.191.255    18   255.255.192.0     16,382      AVL  isPrivate
172.31.192.0      172.31.223.255    19   255.255.224.0     8,190       AVL  isPrivate
172.31.224.0      172.31.239.255    20   255.255.240.0     4,094       AVL  isPrivate
172.31.240.0      172.31.243.255    22   255.255.252.0     1,022       AVL  isPrivate
172.31.244.0      172.31.245.255    23   255.255.254.0     510         AVL  isPrivate
172.31.246.0      172.31.246.255    24   255.255.255.0     254         REQ 252  isPrivate
172.31.247.0      172.31.247.255    24   255.255.255.0     254         REQ 252  isPrivate
172.31.248.0      172.31.248.255    24   255.255.255.0     254         REQ 252  isPrivate
172.31.249.0      172.31.249.255    24   255.255.255.0     254         REQ 252  isPrivate
172.31.250.0      172.31.250.255    24   255.255.255.0     254         REQ 252  isPrivate
172.31.251.0      172.31.251.255    24   255.255.255.0     254         REQ 252  isPrivate
172.31.252.0      172.31.252.255    24   255.255.255.0     254         REQ 252  isPrivate
172.31.253.0      172.31.253.255    24   255.255.255.0     254         REQ 252  isPrivate
172.31.254.0      172.31.254.255    24   255.255.255.0     254         REQ 252  isPrivate
172.31.255.0      172.31.255.255    24   255.255.255.0     254         REQ 252  isPrivate

Answer 6

There's also: http://subnetmask.info/

This has a lot more options than http://www.subnet-calculator.com/cidr.php mentioned by MarkM, but it's also uglier and not as simple.

Which ever one suits your needs.