Copyright 2016-2024 Caleb Evans
Released under the MIT license
CIDR Brewer is a command-line utility which displays information for classless IP addresses (such as subnet mask and network ID) so you don't need to perform the calculations yourself.
You can install CIDR Brewer via pip (ideally globally):
pip install cidr-brewer
To use, run cidr-brewer from the command line with one or two IP addresses.
If you pass a single IP address using slash notation, CIDR Brewer will compute the subnet mask, network ID, broadcast ID, and the range of valid/available IP addresses.
$ cidr-brewer 192.168.19.100/25
Given IP address:
192.168.19.100/25 11000000.10101000.00010011.01100100
Subnet mask:
255.255.255.128 11111111.11111111.11111111.10000000
Network ID:
192.168.19.0/25 11000000.10101000.00010011.00000000
Broadcast ID:
192.168.19.127 11000000.10101000.00010011.01111111
First Available Address:
192.168.19.1 11000000.10101000.00010011.00000001
Last Available Address:
192.168.19.126 11000000.10101000.00010011.01111110
Subnet Size: 2^7 - 2 = 126
Additionally, if you supply a list of block sizes, CIDR Brewer will compute the same information for each sub-block.
$ cidr-brewer 42.114.152.128/25 --block-sizes 16 64 16 32
Given IP address:
42.114.152.128/25 00101010.01110010.10011000.10000000
Block 1:
Block Size: 2^6 = 64
Network ID:
42.114.152.128/26 00101010.01110010.10011000.10000000
Broadcast ID:
42.114.152.191 00101010.01110010.10011000.10111111
First Available Address:
42.114.152.129 00101010.01110010.10011000.10000001
Last Available Address:
42.114.152.190 00101010.01110010.10011000.10111110
Subnet Size: 2^6 - 2 = 62
Block 2:
Block Size: 2^5 = 32
Network ID:
42.114.152.192/27 00101010.01110010.10011000.11000000
Broadcast ID:
42.114.152.223 00101010.01110010.10011000.11011111
First Available Address:
42.114.152.193 00101010.01110010.10011000.11000001
Last Available Address:
42.114.152.222 00101010.01110010.10011000.11011110
Subnet Size: 2^5 - 2 = 30
Block 3:
Block Size: 2^4 = 16
Network ID:
42.114.152.224/28 00101010.01110010.10011000.11100000
Broadcast ID:
42.114.152.239 00101010.01110010.10011000.11101111
First Available Address:
42.114.152.225 00101010.01110010.10011000.11100001
Last Available Address:
42.114.152.238 00101010.01110010.10011000.11101110
Subnet Size: 2^4 - 2 = 14
Block 4:
Block Size: 2^4 = 16
Network ID:
42.114.152.240/28 00101010.01110010.10011000.11110000
Broadcast ID:
42.114.152.255 00101010.01110010.10011000.11111111
First Available Address:
42.114.152.241 00101010.01110010.10011000.11110001
Last Available Address:
42.114.152.254 00101010.01110010.10011000.11111110
Subnet Size: 2^4 - 2 = 14
If you pass two IP addresses (without slash notation), CIDR Brewer will also compute the largest subnet mask needed for communication between the two addresses.
$ cidr-brewer 172.16.11.74 172.16.11.78
Given IP addresses:
172.16.11.74 10101100.00010000.00001011.01001010
172.16.11.78 10101100.00010000.00001011.01001110
Largest subnet mask allowing communication:
29 bits
255.255.255.248 11111111.11111111.11111111.11111000
Network ID:
172.16.11.72/29 10101100.00010000.00001011.01001000
Broadcast ID:
172.16.11.79 10101100.00010000.00001011.01001111
First Available Address:
172.16.11.73 10101100.00010000.00001011.01001001
Last Available Address:
172.16.11.78 10101100.00010000.00001011.01001110
Subnet Size: 2^3 - 2 = 6
If you pass two IP addresses (with slash notation), CIDR Brewer will also indicate if the IP addresses can already communicate on their respective subnets.
$ cidr-brewer 125.47.32.170/25 125.47.32.53/25
Given IP addresses:
125.47.32.170/25 01111101.00101111.00100000.10101010
125.47.32.53/25 01111101.00101111.00100000.00110101
Can these IP addresses communicate?
No
Largest subnet mask allowing communication:
24 bits
255.255.255.0 11111111.11111111.11111111.00000000
Network ID:
125.47.32.0/24 01111101.00101111.00100000.00000000
Broadcast ID:
125.47.32.255 01111101.00101111.00100000.11111111
First Available Address:
125.47.32.1 01111101.00101111.00100000.00000001
Last Available Address:
125.47.32.254 01111101.00101111.00100000.11111110
Subnet Size: 2^8 - 2 = 254
The /examples directory contains example IP addresses for you to test against
the utility.
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