# js-libp2p-mdns

**Repository Path**: mirrors_libp2p/js-libp2p-mdns

## Basic Information

- **Project Name**: js-libp2p-mdns
- **Description**: libp2p MulticastDNS Peer Discovery
- **Primary Language**: Unknown
- **License**: Apache-2.0
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-08-09
- **Last Updated**: 2026-03-28

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# 📁 Archived - this module has been merged into [js-libp2p](https://github.com/libp2p/js-libp2p/tree/master/packages/peer-discovery-mdns)

# @libp2p/mdns <!-- omit in toc -->

[![libp2p.io](https://img.shields.io/badge/project-libp2p-yellow.svg?style=flat-square)](http://libp2p.io/)
[![Discuss](https://img.shields.io/discourse/https/discuss.libp2p.io/posts.svg?style=flat-square)](https://discuss.libp2p.io)
[![codecov](https://img.shields.io/codecov/c/github/libp2p/js-libp2p-mdns.svg?style=flat-square)](https://codecov.io/gh/libp2p/js-libp2p-mdns)
[![CI](https://img.shields.io/github/actions/workflow/status/libp2p/js-libp2p-mdns/js-test-and-release.yml?branch=master\&style=flat-square)](https://github.com/libp2p/js-libp2p-mdns/actions/workflows/js-test-and-release.yml?query=branch%3Amaster)

> Node.js libp2p mDNS discovery implementation for peer discovery

## Table of contents <!-- omit in toc -->

- [Install](#install)
- [Usage](#usage)
- [MDNS messages](#mdns-messages)
- [API Docs](#api-docs)
- [License](#license)
- [Contribute](#contribute)

## Install

```console
$ npm i @libp2p/mdns
```

## Usage

```Typescript
import { mdns } from '@libp2p/mdns'

const options = {
  peerDiscovery: [
    mdns()
  ]
}

async function start () {
  const libp2p = await createLibp2p(options)

  libp2p.on('peer:discovery', function (peerId) {
    console.log('found peer: ', peerId.toB58String())
  })

  await libp2p.start()
}

```

- options
  - `peerName` - Peer name to announce (should not be peeer id), default random string
  - `multiaddrs` - multiaddrs to announce
  - `broadcast` - (true/false) announce our presence through mDNS, default `false`
  - `interval` - query interval, default 10 \* 1000 (10 seconds)
  - `serviceTag` - name of the service announce , default 'ipfs.local\`


## MDNS messages

A query is sent to discover the IPFS nodes on the local network

```js
{
  type: 'query',
  questions: [ { name: 'ipfs.local', type: 'PTR' } ]
}
```

When a query is detected, each IPFS node sends an answer about itself

```js
    [ { name: 'ipfs.local',
        type: 'PTR',
        class: 'IN',
        ttl: 120,
        data: 'QmNPubsDWATVngE3d5WDSNe7eVrFLuk38qb9t6vdLnu2aK.ipfs.local' },
      { name: 'QmNPubsDWATVngE3d5WDSNe7eVrFLuk38qb9t6vdLnu2aK.ipfs.local',
        type: 'SRV',
        class: 'IN',
        ttl: 120,
        data:
         { priority: 10,
           weight: 1,
           port: '20002',
           target: 'LAPTOP-G5LJ7VN9' } },
      { name: 'QmNPubsDWATVngE3d5WDSNe7eVrFLuk38qb9t6vdLnu2aK.ipfs.local',
        type: 'TXT',
        class: 'IN',
        ttl: 120,
        data: ['QmNPubsDWATVngE3d5WDSNe7eVrFLuk38qb9t6vdLnu2aK'] },
      { name: 'LAPTOP-G5LJ7VN9',
        type: 'A',
        class: 'IN',
        ttl: 120,
        data: '127.0.0.1' },
      { name: 'LAPTOP-G5LJ7VN9',
        type: 'AAAA',
        class: 'IN',
        ttl: 120,
        data: '::1' } ]
```

## API Docs

- <https://libp2p.github.io/js-libp2p-mdns>

## License

Licensed under either of

- Apache 2.0, ([LICENSE-APACHE](LICENSE-APACHE) / <http://www.apache.org/licenses/LICENSE-2.0>)
- MIT ([LICENSE-MIT](LICENSE-MIT) / <http://opensource.org/licenses/MIT>)

## Contribute

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.