IPv4 Range Expander

Convert start and end IPv4 addresses (e.g. `192.168.1.1` to `192.168.1.254`) into minimal matching CIDR subnets. Also lists all individual IP addresses contained within the specified range.

Why Use This Tool?

• Firewall Rule Setup: Convert IP address ranges provided by vendors into clean CIDR blocks for AWS Security Groups or ufw rules.
• IP Address Management (IPAM): Expand IP ranges into itemized lists for inventory auditing.
• Routing Aggregation: Group consecutive IP ranges into optimal CIDR blocks.

How to Use

1. Enter Start IPv4 Address (e.g. `192.168.1.0`).
2. Enter End IPv4 Address (e.g. `192.168.1.255`).
3. View matching minimal CIDR block (`192.168.1.0/24`) and total IP count.

Real Working Example

Input:

Start IP: 10.0.0.0 | End IP: 10.0.3.255

Output Result:

Optimal CIDR Blocks: 10.0.0.0/22 | Total IP Count: 1,024 IP Addresses

Important Technical Details & Standards

• Range-to-CIDR Greedy Algorithm: Iteratively computes maximum power-of-two subnets that fit cleanly between start and end integer IPs.
• Itemized IP List Export: Option to generate and download all expanded IP addresses as a `.txt` list.
• 100% Client-Side Engine: Fast local execution in browser memory.

Related Networking & Security Tools

• CIDR Aggregator: Merge adjacent CIDR blocks.
• IPv4 Subnet Calculator: Calculate CIDR subnets and hosts.
• VLSM Calculator: Allocate subnets by host requirements.