Whatmask (Python Version)

A fast, lightweight tool for analyzing IP subnet masks, ranges, and ownership information.
This version uses only native Python and the system whois command — no extra modules required.

Features

• Accepts:
  • CIDR format (e.g., /24)
  • Dotted netmask (e.g., 255.255.255.0)
  • Hexadecimal netmask (e.g., 0xffffff00)
  • Wildcard mask (e.g., 0.0.0.255)
  • Full IP/mask combinations (e.g., 192.168.1.10/24)
• Outputs:
  • CIDR notation
  • Dotted decimal netmask
  • Hexadecimal netmask
  • Wildcard mask
  • Number of usable IP addresses
  • Network address and broadcast address
  • First and last usable IPs
• Colorized warnings for unusual subnets (/31, /32)
• WHOIS lookup using system whois to find:
  • Organization
  • Country
• Brief mode for compact one-line output
• Smart error handling:
  • Detects if user inputs an IP instead of a netmask
  • Clean guidance if mistakes are made

Installation

1. Clone the repository:

git clone https://github.com/YOUR_USERNAME/whatmask-python.git
cd whatmask-python
chmod +x getmask.py

2. (Optional) Install globally:

sudo cp getmask.py /usr/local/bin/whatmask

Now you can run whatmask from anywhere.

Install via Homebrew:

brew tap willcurtis/tools
brew install mac-lookup-tool

Dependencies

• Python 3.6+
• System whois command

If needed, install whois:

# Ubuntu/Debian
sudo apt install whois

# RedHat/CentOS
sudo yum install whois

# macOS (Homebrew)
brew install whois

Usage

Standard Mode

./getmask.py 192.168.1.10 255.255.255.0
./getmask.py 192.168.1.10/255.255.255.0
./getmask.py 192.168.1.10/24

Brief Mode

Outputs a compact single line:

./getmask.py --brief 192.168.1.10/24

Example:

CIDR: /24 | Network: 192.168.1.0 | Broadcast: 192.168.1.255 | Range: 192.168.1.1-192.168.1.254

WHOIS Lookup

Displays organization and country from the system's whois command:

./getmask.py --whois 8.8.8.8/24

Warnings

• ⚠️ If you input a /31 or /32 network, a colored warning is displayed:

  • /31: Two-host subnet, point-to-point links
  • /32: Single IP (host route)

• ⚠️ If you accidentally input an IP address without a subnet mask,
  you are advised to use the correct format:

Example:

⚠️ Input 192.168.0.1 looks like an IP address, not a netmask.
⚠️ Hint: Use IP/mask format like 192.168.0.1/24

License

MIT License — see LICENSE for full terms.