arp-lookup

About

arp-lookup is a simple ARP utility to map an IP address to a MAC address and vice versa.

Vendor information has been removed from v2 in favor of @network-utils/vender-lookup
Please see the CHANGELOG.md for the full list of breaking changes

Installation

$ npm install @network-utils/arp-lookup

Usage

Example

import arp from '@network-utils/arp-lookup'
// Or
import {toMAC, toIP, ...} from '@network-utils/arp-lookup'

// Retrieve the corresponding IP address for a given MAC address
await arp.toIP('04-A1-51-1B-12-92') // Or '04:a1:51:1b:12:92' (any valid MAC format)
// Result: "192.168.2.47"

// Retrieve the corresponding MAC address for a given IP address
await arp.toMAC('192.168.2.47')
// Result: "04:a1:51:1b:12:92" 👈🏼 All MAC addresses are normalized to this format

arp.isMAC('04-a1:51:1B-12-92') // true
arp.isMAC('not:a:mac') // false

arp.isIP('192.168.2.47') // true
arp.isIP('not.an.ip') // false

// Note: Unavailable on darwin based systems.
await arp.isType('dynamic', '192.168.2.47') // true
await arp.isType('dynamic', '04:a1:51:1b:12:92') // true
await arp.isType('static', '192.168.2.255') // true
await arp.isType('static', 'ff:ff:ff:ff:ff:ff') // true
await arp.isType('undefined', '0.0.0.0') // true

// Note: `type` property is always set to `"unknown"` on darwin systems
await arp.getTable()
// Result:
[
    { ip: '192.168.137.255', mac: 'ff:ff:ff:ff:ff:ff', type: 'static' },
    { ip: '224.0.0.22', mac: '01:00:5e:00:00:16', type: 'static' },
    { ip: '224.0.0.251', mac: '01:00:5e:00:00:fb', type: 'static' },
    { ip: '224.0.0.252', mac: '01:00:5e:00:00:fc', type: 'static' },
    { ip: '239.255.255.250', mac: '01:00:5e:7f:ff:fa', type: 'static' },
    { ip: '192.168.2.1', mac: '04:a1:51:1b:12:92', type: 'dynamic' },
    { ip: '192.168.2.3', mac: '1a:b1:61:2f:14:72', type: 'dynamic' },
    { ip: '192.168.2.255', mac: 'ff:ff:ff:ff:ff:ff', type: 'static' },
    { ip: '224.0.0.2', mac: '01:00:5e:00:00:02', type: 'static' },
    ...
]


// Note: `type` property is always set to `"unknown"` on Unix systems
await arp.fromPrefix('01:00:5e')
// Result:
[
    { ip: '224.0.0.22', mac: '01:00:5e:00:00:16', type: 'static' },
    { ip: '224.0.0.251', mac: '01:00:5e:00:00:fb', type: 'static' },
    { ip: '224.0.0.252', mac: '01:00:5e:00:00:fc', type: 'static' },
    { ip: '239.255.255.250', mac: '01:00:5e:7f:ff:fa', type: 'static' },
    { ip: '224.0.0.2', mac: '01:00:5e:00:00:02', type: 'static' },
    ...
]

getTable(): Promise<IArpTable>

Returns a promise containing the parsed output of $ arp -a with the addition of a vendor field.
Note that the type property is always set to "unknown" on Unix systems

toMAC(ip: string): Promise<string | null>

Returns a promise containing the MAC that relates to ip or null if a match couldn't be made.
Throws an "Invalid IP" error if ip is not a valid IP address

toIP(mac: string): Promise<string | null>

Returns a promise containing the IP that relates to mac or null if a match couldn't be made.
Throws an "Invalid MAC" error if mac is not a valid MAC address

fromPrefix(prefix: string): Promise<IArpTableRow[]>

Returns any devices on the network with the specified MAC prefix, or an empty array if none exist.
Throws an "Invalid Prefix" error if prefix is not a valid MAC address prefix

isType(type: 'static' | 'dynamic' | 'unknown' | 'undefined', address: string): Promise<boolean>

• address can be any valid IP or MAC address

Returns a promise containing a boolean which indicates the record for address is type.
Pass type = "undefined" to determine if a record for address exists or not.
This method is useless on Unix based systems because $ arp -a doesn't return the type for an address
Throws an "Invalid address" error if address is not a valid IP or MAC address

isMAC(mac: string): boolean

Checks if a MAC address is valid

isPrefix(prefix: string): boolean

Checks if a MAC address prefix is valid

isIP(ip: string): boolean

Checks if an IP address is valid

IArpTableRow

IArpTableRow {
  ip: string
  mac: string
  type: 'static' | 'dynamic' | 'unknown'
}

IArpTable

An array of IArpTableRow's.

type IArpTable = IArpTableRow[]

Testing

$ git clone https://github.com/justintaddei/arp-lookup.git
$ cd arp-lookup
$ npm install
$ npm test

License

MIT