ipsubnet

An IP subnetting and addressing calculator for the command line. Give it an IP address with a subnet mask or CIDR prefix. It prints the network address, broadcast address, usable host range and host counts, and it can split the network into a list of subnets. It works with IPv4 and IPv6 on Windows, macOS and Linux.

Install

Windows (PowerShell):

irm https://raw.githubusercontent.com/ShazanZaidii/ipsubnet/main/scripts/install.ps1 | iex

macOS / Linux:

curl -fsSL https://raw.githubusercontent.com/ShazanZaidii/ipsubnet/main/scripts/install.sh | sh

With Python (any OS, Python 3.8+):

pip install ipsubnet

or, to keep it isolated from other packages, pipx install ipsubnet.

You can also download a ready-to-run binary from the Releases page:

On macOS and Linux, run chmod +x on the file first. On macOS, if you downloaded it with a browser, also run xattr -d com.apple.quarantine <file>.

Usage

ipsubnet ADDRESS[/PREFIX] [MASK] [--prefix N | --subnets N | --hosts N] [options]

If you run ipsubnet with no arguments, it starts in interactive mode and asks for each value. This is also what happens when you double-click the Windows .exe.

Example

$ ipsubnet 192.168.1.10/24 --hosts 50

  Address          192.168.1.10
  Network          192.168.1.0/24
  Netmask          255.255.255.0  (/24)
  Wildcard         0.0.0.255
  Network address  192.168.1.0
  Broadcast        192.168.1.255
  Usable range     192.168.1.1 - 192.168.1.254
  Usable hosts     254
  Total addresses  256
  Class            C
  Type             Private

  Binary  (network bits | host bits)
  Address          11000000.10101000.00000001.00001010
  Netmask          11111111.11111111.11111111.00000000
  Network          11000000.10101000.00000001.00000000
  Broadcast        11000000.10101000.00000001.11111111

  Subnets  192.168.1.0/24 into /26: 4 subnets, 62 usable hosts each

  #  Subnet            First host     Last host      Broadcast      Usable
  -  ----------------  -------------  -------------  -------------  ------
  1  192.168.1.0/26    192.168.1.1    192.168.1.62   192.168.1.63       62
  2  192.168.1.64/26   192.168.1.65   192.168.1.126  192.168.1.127      62
  3  192.168.1.128/26  192.168.1.129  192.168.1.190  192.168.1.191      62
  4  192.168.1.192/26  192.168.1.193  192.168.1.254  192.168.1.255      62

How it works

• Network address: the IP AND the subnet mask (all host bits set to 0).
• Broadcast address: the network address with all host bits set to 1.
• Usable hosts: 2^(32 − prefix) − 2 for IPv4, because the network and broadcast addresses can't be assigned to hosts. A /31 has 2 usable addresses (point-to-point links, RFC 3021) and a /32 has 1.
• Subnetting: borrowing b host bits creates 2^b subnets of prefix + b.
  • --subnets N borrows ⌈log₂ N⌉ bits.
  • --hosts N keeps ⌈log₂(N + 2)⌉ host bits.
• IPv6 has no broadcast address, so every address in the prefix is counted as usable.

Development

pip install -e .
python -m unittest discover -s tests -v

Pushing a tag like v1.0.1 makes GitHub Actions run the tests on all three operating systems, build the binaries and publish a release.

Authors

Group 4: Shazan Hussain Zaidi, Harshit Agrawal, Prabhat Bhati