# is-loopback-addr

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> Check if a IP address is a loopback address

Various Internet Engineering Task Force ([IETF](https://www.ietf.org/)) standards reserve the IPv4 address block `127.0.0.0/8` and the IPv6 address `::1/128` for this purpose. The most common IPv4 address used is 127.0.0.1. Commonly these loopback addresses are mapped to the hostnames, localhost or loopback. For more information check [rfc5735](https://tools.ietf.org/html/rfc5735) and [rfc3513](https://tools.ietf.org/html/rfc3513#section-2.4).

## Install

```sh
npm i is-loopback-addr
```

## Usage

```js
const isLoopbackAddr = require('is-loopback-addr')

console.log(isLoopbackAddr('127.0.0.1')) // true
console.log(isLoopbackAddr('192.168.0.1')) // false
console.log(isLoopbackAddr('22.2.0.1')) // false
console.log(isLoopbackAddr('::1')) // true
console.log(isLoopbackAddr('2001:8a0:7ac5:4201:3ac9:86ff:fe31:7095')) // false
```

## Contribute

Feel free to dive in! [Open an issue](https://github.com/vasco-santos/is-loopback-addr/issues/new) or submit PRs.

## License

[MIT](LICENSE) © Vasco Santos

Check if a IP address is a loopback address. 

Meet the Socket Team at RSAC and BSidesSF 2026, March 23–26

is-loopback-addr

Check if a IP address is a loopback address

vascosantos

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is-loopback-addr

is-loopback-addr

Install

Usage

Contribute

License

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