# IPv4 address classify

`ipv4-address-classify` · version 1.0.0 · URLs & IP addresses · free, no key needed

Classify an IPv4 address against the static IANA IPv4 special-purpose address registry.

**Use when you need to: ipv4 address classify · is ipv4 private · ipv4 special purpose lookup.**

## Supported

- ipv4 address classify
- is ipv4 private
- ipv4 special purpose lookup

## Not supported

- IPv6
- routing-table-aware or organization-specific reservations
- live registry lookups

## Behavior

- address is a canonical dotted-decimal IPv4 address.
- classification is the single most-specific (longest-prefix) matching label from a fixed, embedded table of well-known IANA IPv4 special-purpose ranges; "public" if no entry matches.
- Labels: this_network (0.0.0.0/8), private (RFC 1918), shared_address_space (100.64.0.0/10), loopback (127.0.0.0/8), link_local (169.254.0.0/16), reserved (192.0.0.0/24, 192.88.99.0/24, 240.0.0.0/4), documentation (TEST-NET-1/2/3), benchmarking (198.18.0.0/15), multicast (224.0.0.0/4), broadcast (255.255.255.255/32), public (everything else).
- matched_range is the exact embedded CIDR entry that matched, or null when classification is "public".

## Input

- `address` (string, required): max length 15; pattern `^(?:0|[1-9][0-9]{0,2})(?:\.(?:0|[1-9][0-9]{0,2})){3}$`

## Output

- `classification` (one of "this_network", "private", "shared_address_space", "loopback", "link_local", "reserved", "documentation", "benchmarking", "multicast", "broadcast", "public", required)
- `matched_range` (string or null, required): max length 18

## Limits

- Request body up to 256 KiB

## Example

Request input:

```json
{
  "address": "192.168.1.1"
}
```

Response:

```json
{
  "result": {
    "classification": "private",
    "matched_range": "192.168.0.0/16"
  }
}
```

## How to call it

### MCP

Connect `https://computefirst.net/mcp` ([setup](/docs#connect)), then call `execute` with:

```json
{
  "id": "ipv4-address-classify",
  "version": "1.0.0",
  "input": {
    "address": "192.168.1.1"
  }
}
```

### HTTP (no key)

```sh
curl -X POST https://computefirst.net/v1/tools/ipv4-address-classify/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"address":"192.168.1.1"}'
```

The machine-readable contract is at [/v1/tools/ipv4-address-classify/versions/1.0.0](/v1/tools/ipv4-address-classify/versions/1.0.0).

### CLI

```sh
node cli.mjs run ipv4-address-classify 1.0.0 --input input.json --base-url https://computefirst.net
```

Get the client at [/clients/cli/](/clients/cli/).

## Related tools

- [IPv6 address classify](/tools/ipv6-address-classify): Classify an IPv6 address against the static IANA IPv6 special-purpose address registry.
- [IPv4 address compare](/tools/ipv4-address-compare): Compare two canonical IPv4 addresses by their numeric uint32 value.
- [IPv4 address distance](/tools/ipv4-address-distance): Compute the signed integer distance between two IPv4 addresses (address_b minus address_a).
- [IPv4 address offset](/tools/ipv4-address-offset): Add a signed integer offset to an IPv4 address, throwing if the result leaves the IPv4 address space.
- [IPv4 in CIDR](/tools/ipv4-in-cidr): Test whether a canonical IPv4 address lies in a CIDR prefix whose host bits are zero.
- [IPv4 range to cidrs](/tools/ipv4-range-to-cidrs): Convert an arbitrary IPv4 address range into the minimal list of CIDR blocks that exactly covers it.