vpc-free

Find free IP address blocks in AWS EC2

This script searches for the largest available IP subnets within the unallocated spaces between your VPC subnets, or between VPCs for a given CIDR block.

Installation

Install vpc-free to /usr/local/bin with:

$ pip install vpc-free

The script uses the Amazon AWS SDK (boto3) to connect to AWS. The SDK must be configured with credentials to connect to the AWS APIs. Please see the Boto3 documentation for instruction.

Usage

$ vpc-free -h
usage: vpc-free [-h] TARGET

Find free IP blocks in AWS EC2.

positional arguments:
  TARGET      CIDR, VPC ID or VPC Name to search

optional arguments:
  -h, --help  show this help message and exit

Examples

# search for unallocated blocks between VPCs in 10.0.0.0/8
$ vpc-free 10.0.0.0/8
MIN IP    MAX IP         MASK SIZE     BEST         LABEL
10.0.0.0  10.63.255.255  /10  4194304  10.0.0.0/10  FREE
10.64.0.0 10.64.255.255  /16  65536                 vpc-c4871ca0 (Demo)
10.65.0.0 10.255.255.255      12517376 10.128.0.0/9 FREE

# search for unallocated blocks between subnets in a VPC
$ vpc-free vpc-c4671caf
10.64.0.0  10.64.15.255  /20  4096                 subnet-74247002 (Subnet 1)
10.64.16.0 10.64.31.255  /20  4096                 subnet-d32421a5 (Subnet 2)
10.64.32.0 10.64.47.255  /20  4096  10.64.32.0/20  FREE
10.64.48.0 10.64.63.255  /20  4096                 subnet-0a257077 (Subnet 4)
10.64.64.0 10.64.255.255      49152 10.64.128.0/17 FREE