Linux Command line tool to work with netmasks / CIDR notation

Question

I'm terrible at working out network subnets in my head. Is there some command line tool for linux (ubuntu packages a plus), that lets me put in 255.255.255.224 and it'll tell me that is a /27?

Answer 1

ipcalc can do this, for example:

[kbrandt@kbrandt-opadmin: ~] ipcalc 192.168.1.1/24                 
Address:   192.168.1.1          11000000.10101000.00000001. 00000001
Netmask:   255.255.255.0 = 24   11111111.11111111.11111111. 00000000
Wildcard:  0.0.0.255            00000000.00000000.00000000. 11111111
=>
Network:   192.168.1.0/24       11000000.10101000.00000001. 00000000
HostMin:   192.168.1.1          11000000.10101000.00000001. 00000001
HostMax:   192.168.1.254        11000000.10101000.00000001. 11111110
Broadcast: 192.168.1.255        11000000.10101000.00000001. 11111111
Hosts/Net: 254                   Class C, Private Internet

if you entered a subnet mask instead of CIDR, you will still see the /## CIDR number after 'Network:', so it goes both ways.

or with sipcalc:

[kbrandt@kbrandt-opadmin: ~] sipcalc 192.168.1.1/24                                                                                             <23403@8:55>
-[ipv4 : 192.168.1.1/24] - 0
[CIDR]
Host address    	- 192.168.1.1
Host address (decimal)  - 3232235777
Host address (hex)  - C0A80101
Network address 	- 192.168.1.0
Network mask    	- 255.255.255.0
Network mask (bits) - 24
Network mask (hex)  - FFFFFF00
Broadcast address   - 192.168.1.255
Cisco wildcard  	- 0.0.0.255
Addresses in network    - 256
Network range   	- 192.168.1.0 - 192.168.1.255
Usable range    	- 192.168.1.1 - 192.168.1.254

The Ubuntu Packages are ipcalc and sipcalc:

sudo apt-get install ipcalc
sudo apt-get install sipcalc

Answer 2

I've used ipcalc before for this. It looks like Ubuntu also has sipcalc. See here.

Answer 3

Try either sipcalc or ipcalc.

Answer 4

I use ipcalc for network subnetting, but it's limited to IPv4 addresses.
you can use subnetcalc, it support both of IPv4 and IPv6.