Useful but Unknown Unix Tools: Calculating with IPs, The Sequel //at 20:09 //by abe

This is a direct followup on my previous blog posting about calculating IPs and netmasks with the tools netmask and prips. Kurt Roeckx (via e-mail) and Niall Donegan (via a comment to that blog posting) both told me about the package sipcalc, and Kurt also mentioned the package ipcalc. Thanks for that! And since I found both useful, too, let’s put them in their own blog posting:

Both tools, ipcalc and sipcalc offer a “get all information at once” mode which are not present in the previously presented tool netmask.

ipcalc

ipcalc by default outputs all information and even in ANSI colors:

$ ipcalc 192.168.96.0/21
Address:   192.168.96.0         11000000.10101000.01100 000.00000000
Netmask:   255.255.248.0 = 21   11111111.11111111.11111 000.00000000
Wildcard:  0.0.7.255            00000000.00000000.00000 111.11111111
=>
Network:   192.168.96.0/21      11000000.10101000.01100 000.00000000
HostMin:   192.168.96.1         11000000.10101000.01100 000.00000001
HostMax:   192.168.103.254      11000000.10101000.01100 111.11111110
Broadcast: 192.168.103.255      11000000.10101000.01100 111.11111111
Hosts/Net: 2046                  Class C, Private Internet

(Coloured “Screenshots” done with ANSI HTML Adapter from the package aha.)

You can suppress the bitwise option or directly output HTML via commandline options. For example ipcalc -b -h 192.168.96.0/21 outputs the following content:

Address:	192.168.96.0
Netmask:	255.255.248.0 = 21
Wildcard:	0.0.7.255
=>
Network:	192.168.96.0/21
HostMin:	192.168.96.1
HostMax:	192.168.103.254
Broadcast:	192.168.103.255
Hosts/Net:	2046	Class C, Private Internet

Yes, that’s an HTML table and no preformatted text, just with a monospaced font. (I just removed the hardcoded text color from it, otherwise it would not look nice on dark backgrounds like in Planet Commandline’s default color scheme.)

Like netmask, ipcalc can also deaggregate IP ranges into largest possible networks:

$ ipcalc 192.168.87.0 - 192.168.110.255
deaggregate 192.168.87.0 - 192.168.110.255
192.168.87.0/24
192.168.88.0/21
192.168.96.0/21
192.168.104.0/22
192.168.108.0/23
192.168.110.0/24

(ipcalc -r 192.168.87.0 192.168.110.255 is just another way to write this, and it results in the same output.)

To find networks with at least 20, 63 and 30 IP addresses within a /24 network, use for example:

Address:   192.0.2.0            
Netmask:   255.255.255.0 = 24   
Wildcard:  0.0.0.255            
=>
Network:   192.0.2.0/24         
HostMin:   192.0.2.1            
HostMax:   192.0.2.254          
Broadcast: 192.0.2.255          
Hosts/Net: 254                   Class C

1. Requested size: 20 hosts
Netmask:   255.255.255.224 = 27 
Network:   192.0.2.128/27       
HostMin:   192.0.2.129          
HostMax:   192.0.2.158          
Broadcast: 192.0.2.159          
Hosts/Net: 30                    Class C

2. Requested size: 63 hosts
Netmask:   255.255.255.128 = 25 
Network:   192.0.2.0/25         
HostMin:   192.0.2.1            
HostMax:   192.0.2.126          
Broadcast: 192.0.2.127          
Hosts/Net: 126                   Class C

3. Requested size: 30 hosts
Netmask:   255.255.255.224 = 27 
Network:   192.0.2.160/27       
HostMin:   192.0.2.161          
HostMax:   192.0.2.190          
Broadcast: 192.0.2.191          
Hosts/Net: 30                    Class C

Needed size:  192 addresses.
Used network: 192.0.2.0/24
Unused:
192.0.2.192/26

sipcalc

sipcalc is similar to ipcalc. One big difference seems to be the IPv6 support:

$ sipcalc 2001:DB8::/32
-[ipv6 : 2001:DB8::/32] - 0

[IPV6 INFO]
Expanded Address        - 2001:0db8:0000:0000:0000:0000:0000:0000
Compressed address      - 2001:db8::
Subnet prefix (masked)  - 2001:db8:0:0:0:0:0:0/32
Address ID (masked)     - 0:0:0:0:0:0:0:0/32
Prefix address          - ffff:ffff:0:0:0:0:0:0
Prefix length           - 32
Address type            - Aggregatable Global Unicast Addresses
Network range           - 2001:0db8:0000:0000:0000:0000:0000:0000 -
                          2001:0db8:ffff:ffff:ffff:ffff:ffff:ffff

(Thanks to Niall for the pointer to RFC3849. :-)

It can also split up networks into smaller chunks, but only same-size chunks, like e.g. split a /32 IPv6 network into /34 networks:

sipcalc -S34 2001:DB8::/32
-[ipv6 : 2001:DB8::/32] - 0

[Split network]
Network                 - 2001:0db8:0000:0000:0000:0000:0000:0000 -
                          2001:0db8:3fff:ffff:ffff:ffff:ffff:ffff
Network                 - 2001:0db8:4000:0000:0000:0000:0000:0000 -
                          2001:0db8:7fff:ffff:ffff:ffff:ffff:ffff
Network                 - 2001:0db8:8000:0000:0000:0000:0000:0000 -
                          2001:0db8:bfff:ffff:ffff:ffff:ffff:ffff
Network                 - 2001:0db8:c000:0000:0000:0000:0000:0000 -
                          2001:0db8:ffff:ffff:ffff:ffff:ffff:ffff

-

Similar thing with IPv4:

sipcalc -s27 192.0.2.0/24
-[ipv4 : 192.0.2.0/24] - 0

[Split network]
Network                 - 192.0.2.0       - 192.0.2.31
Network                 - 192.0.2.32      - 192.0.2.63
Network                 - 192.0.2.64      - 192.0.2.95
Network                 - 192.0.2.96      - 192.0.2.127
Network                 - 192.0.2.128     - 192.0.2.159
Network                 - 192.0.2.160     - 192.0.2.191
Network                 - 192.0.2.192     - 192.0.2.223
Network                 - 192.0.2.224     - 192.0.2.255

sipcalc also has a “show me all information” mode with the -a option:

$ sipcalc -a 192.168.96.0/21
-[ipv4 : 192.168.96.0/21] - 0

[Classfull]
Host address            - 192.168.96.0
Host address (decimal)  - 3232260096
Host address (hex)      - C0A86000
Network address         - 192.168.96.0
Network class           - C
Network mask            - 255.255.255.0
Network mask (hex)      - FFFFFF00
Broadcast address       - 192.168.96.255

[CIDR]
Host address            - 192.168.96.0
Host address (decimal)  - 3232260096
Host address (hex)      - C0A86000
Network address         - 192.168.96.0
Network mask            - 255.255.248.0
Network mask (bits)     - 21
Network mask (hex)      - FFFFF800
Broadcast address       - 192.168.103.255
Cisco wildcard          - 0.0.7.255
Addresses in network    - 2048
Network range           - 192.168.96.0 - 192.168.103.255
Usable range            - 192.168.96.1 - 192.168.103.254

[Classfull bitmaps]
Network address         - 11000000.10101000.01100000.00000000
Network mask            - 11111111.11111111.11111111.00000000

[CIDR bitmaps]
Host address            - 11000000.10101000.01100000.00000000
Network address         - 11000000.10101000.01100000.00000000
Network mask            - 11111111.11111111.11111000.00000000
Broadcast address       - 11000000.10101000.01100111.11111111
Cisco wildcard          - 00000000.00000000.00000111.11111111
Network range           - 11000000.10101000.01100000.00000000 -
                          11000000.10101000.01100111.11111111
Usable range            - 11000000.10101000.01100000.00000001 -
                          11000000.10101000.01100111.11111110

[Networks]
Network                 - 192.168.96.0    - 192.168.103.255 (current)

Thanks again to Kurt and Niall for their contributions!

Now listening to the schreimaschine and fausttanz submissions for the interactive competition at the Bünzli/DemoDays in Olten (Switzerland)