IPv4 CIDR overlap

ipv4-cidr-overlap · version 1.0.0 · URLs & IP addresses · free, no key needed

Test whether two IPv4 CIDR blocks overlap (share at least one address).

Use when you need to: ipv4 cidr overlap · check ipv4 subnet overlap · ipv4 cidr intersects.

Supported

• ipv4 cidr overlap
• check ipv4 subnet overlap
• ipv4 cidr intersects

Not supported

• IPv6

Behavior

• cidr_a and cidr_b are each dotted-decimal/prefix with host bits zero; otherwise the tool throws.
• overlap is true iff the two blocks share at least one address, including when one fully contains the other or they are identical.

Input

• cidr_a (string, required): max length 18
• cidr_b (string, required): max length 18

Output

• overlap (boolean, required)
• network_a (string, required): max length 18
• network_b (string, required): max length 18

Limits

• max cidr length: 18

Example

Request input:

{
  "cidr_a": "10.0.0.0/16",
  "cidr_b": "10.0.128.0/17"
}

Response:

{
  "result": {
    "overlap": true,
    "network_a": "10.0.0.0/16",
    "network_b": "10.0.128.0/17"
  }
}

How to call it

MCP

Connect https://computefirst.net/mcp (setup), then call execute with:

{
  "id": "ipv4-cidr-overlap",
  "version": "1.0.0",
  "input": {
    "cidr_a": "10.0.0.0/16",
    "cidr_b": "10.0.128.0/17"
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/ipv4-cidr-overlap/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"cidr_a":"10.0.0.0/16","cidr_b":"10.0.128.0/17"}'

The machine-readable contract is at /v1/tools/ipv4-cidr-overlap/versions/1.0.0.

CLI

node cli.mjs run ipv4-cidr-overlap 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• IPv6 CIDR overlap: Test whether two IPv6 CIDR blocks overlap (share at least one address).
• IPv4 CIDR contains: Test whether one IPv4 CIDR block fully contains another IPv4 CIDR block.
• IPv4 CIDR parse: Parse an IPv4 CIDR block into its network, broadcast, netmask, wildcard mask, usable host range and address counts.
• IPv4 in CIDR: Test whether a canonical IPv4 address lies in a CIDR prefix whose host bits are zero.
• IPv6 CIDR contains: Test whether one IPv6 CIDR block fully contains another IPv6 CIDR block.
• IPv4 CIDR aggregate: Merge a list of IPv4 CIDR blocks into the minimal equivalent list of non-overlapping CIDR blocks.