Quick Start

Get your first CIDR allocation in under 5 minutes.

Installation

npm

npm install -g subnetter

yarn

yarn global add subnetter

npx (no install)

# Run directly without installing
npx subnetter --version

Verify the installation:

subnetter --version

Prerequisites

• Node.js: ^18.18.0 || ^20.9.0 || >=21.1.0
• npm or yarn

Your First Allocation

1. Create a configuration file

   Create a file named config.json:

   {
     "baseCidr": "10.0.0.0/16",
     "accounts": [
       {
         "name": "production",
         "clouds": {
           "aws": {
             "regions": ["us-east-1", "us-west-2"]
           }
         }
       }
     ],
     "subnetTypes": {
       "Public": 24,
       "Private": 24,
       "Data": 26
     }
   }

2. Generate allocations

   subnetter generate --config config.json --output allocations.csv

3. View your allocations

   Open allocations.csv to see your subnet allocations:

   Account	Cloud	Region	AZ	Subnet	CIDR	Usable IPs
   production	aws	us-east-1	us-east-1a	Public	10.0.0.0/24	254
   production	aws	us-east-1	us-east-1a	Private	10.0.1.0/24	254
   production	aws	us-east-1	us-east-1a	Data	10.0.2.0/26	62
   …	…	…	…	…	…	…

Zero Conflicts

Every CIDR is mathematically guaranteed to be non-overlapping. The same config always produces the same output.

Validate Before Generating

Check your configuration for errors without generating allocations:

subnetter validate --config config.json

Analyze Your Configuration

Get statistics about your configuration:

subnetter analyze --config config.json

Common Options

Option	Short	Description
--config	-c	Path to configuration file (required)
--output	-o	Output CSV file path (default: allocations.csv)
--provider	-p	Filter by cloud provider (aws, azure, gcp)
--verbose	-v	Enable detailed logging
--base-cidr	-b	Override the base CIDR from config

Next Steps

• Configuration Reference - Learn all configuration options
• CLI Reference - Complete command documentation
• Best Practices - CIDR allocation strategies
• CIDR Primer - Learn CIDR notation basics