Getting MAC Address

Question

I need a cross platform method of determining the MAC address of a computer at run time. For windows the 'wmi' module can be used and the only method under Linux I could find was to run ifconfig and run a regex across its output. I don't like using a package that only works on one OS, and parsing the output of another program doesn't seem very elegant not to mention error prone.

Does anyone know a cross platform method (windows and linux) method to get the MAC address? If not, does anyone know any more elegant methods then those I listed above?

Solution 1

Python 2.5 includes an uuid implementation which (in at least one version) needs the mac address. You can import the mac finding function into your own code easily:

from uuid import getnode as get_mac
mac = get_mac()

The return value is the mac address as 48 bit integer.

Solution 2

The pure python solution for this problem under Linux to get the MAC for a specific local interface, originally posted as a comment by vishnubob and improved by on Ben Mackey in this activestate recipe

#!/usr/bin/python

import fcntl, socket, struct

def getHwAddr(ifname):
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    info = fcntl.ioctl(s.fileno(), 0x8927,  struct.pack('256s', ifname[:15]))
    return ':'.join(['%02x' % ord(char) for char in info[18:24]])

print getHwAddr('eth0')

This is the Python 3 compatible code:

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import fcntl
import socket
import struct


def getHwAddr(ifname):
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    info = fcntl.ioctl(s.fileno(), 0x8927,  struct.pack('256s', bytes(ifname, 'utf-8')[:15]))
    return ':'.join('%02x' % b for b in info[18:24])


def main():
    print(getHwAddr('enp0s8'))


if __name__ == "__main__":
    main()

Solution 3

netifaces is a good module to use for getting the mac address (and other addresses). It's crossplatform and makes a bit more sense than using socket or uuid.

import netifaces

netifaces.interfaces()
# ['lo', 'eth0', 'tun2']

netifaces.ifaddresses('eth0')[netifaces.AF_LINK]
# [{'addr': '08:00:27:50:f2:51', 'broadcast': 'ff:ff:ff:ff:ff:ff'}]

---

• pypi location

• Good Intro to netifaces

Solution 4

Sometimes we have more than one net interface.

A simple method to find out the mac address of a specific interface, is:

def getmac(interface):
    try:
        mac = open('/sys/class/net/'+interface+'/address').readline()
    except:
        mac = "00:00:00:00:00:00"
    return mac[0:17]

to call the method is simple

myMAC = getmac("wlan0")

Solution 5

One other thing that you should note is that uuid.getnode() can fake the MAC addr by returning a random 48-bit number which may not be what you are expecting. Also, there's no explicit indication that the MAC address has been faked, but you could detect it by calling getnode() twice and seeing if the result varies. If the same value is returned by both calls, you have the MAC address, otherwise you are getting a faked address.

>>> print uuid.getnode.__doc__
Get the hardware address as a 48-bit positive integer.

    The first time this runs, it may launch a separate program, which could
    be quite slow.  If all attempts to obtain the hardware address fail, we
    choose a random 48-bit number with its eighth bit set to 1 as recommended
    in RFC 4122.

View more solutions

Comments

[sath garcia]

I just tried this on a Windows box and it works great... except that the laptop I tried it on has 2 NICs (one wireless) and there's no way to determine which MAC it returned. Just a word of warning if you want to use this code.

[Martin Beckett]

Thats a feature of the windows device enumerator, whatever method you use to get the address - you have to be carefull if using it as a unique ID.

[Aatch]

-1 He wants a python solution, so you go and give him the same regurgitated C solution plastered throughout the web.

[Aatch]

Used it personally, requires a specific install/compile on each system but works well.

[Frédéric Grosshans]

Not that the value of the 8th is 1 precisely because it cannot be used by a network card. Just checking this bit is enough to detect whether the address is faked or not.

[Frédéric Grosshans]

The check is just done with: if (mac >> 40)%2 : raise OSError, "The system does not seem to have a valid MAC"

[deinonychusaur]

Just a warning: If you look at the getnode documentation it says that it will return a random long if it fails to detect the mac: "If all attempts to obtain the hardware address fail, we choose a random 48-bit number with its eighth bit set to 1 as recommended in RFC 4122." So check that eighth bit!

[screenshot345]

hex(mac) to get the familiar hex format of the mac

[tomlogic]

Or ':'.join(("%012X" % mac)[i:i+2] for i in range(0, 12, 2)) for an uppercase MAC with each byte separated by a colon.

[nu everest]

getnode() returns something different every time I restart my windows 7 laptop.

[chris]

@deinonychusaur I have a valid mac address where the least significant bit of the first octect is 1. So it seems this is not enough to verify the return value. However, mhawke provides a solution in his answer below that might work.

[pQuestions123]

Does this have to do anything with the question?

[Bryce Guinta]

Or ':'.join((itertools.starmap(operator.add, zip(*([iter("%012X" % mac)] * 2))))), an alternative way of doing it @tomlogic

[Richard Aplin]

that bit me in the ass - on an embedded system it returned random value if ethernet jack not connected, however reading /sys/class/net/eth0/address (or parsing output of ifconfig) works either connected or not

[RandomInsano]

Not super useful for OS X or Windows. :|

[svenyonson]

@tomlogic - that works excellent!! Very cryptic, but nice one liner that does just what I needed. ':'.join(("%012X" % mac)[i:i+2] for i in range(0, 12, 2))

[MikeT]

Perfect for Pis!

[Stefano]

that's not really an answer - just a comment

[Donn Lee]

import socket then [addr.address for n in nics for addr in nics[n] if n == 'enp4s0' and addr.family == socket.AF_PACKET] results in ['ab:cd:ef:01:02:03']

[Napolean]

Standard output for above variables: None None None None 00:00:00:00:00:00 None

[Ghost of Goes]

Those are just examples of usage. You need to replace the arguments with the values applicable to your system, which is very likely why you're getting null results. For example, "eth0" is not applicable to a Windows system, and "Ethernet 3" isn't applicable to a Linux system, but both are included above as examples so you know how to use the library on both platforms. Note: "localhost" will always return "00:00:00:00:00:00".

[Sean McCarthy]

Beautiful, works like a charm!

[Pedro A. Aranda]

return mac.strip() may be easier to get rid of the newline ;-)