MAC Randomizer Alfred Script

A recent conversation I had dealt with free wifi that limited the amount of time you could use it before it kicked you off. Now, while I support the right of wifi providers to do as they please, it’s an interesting question. AFAIK most tracking of that sort is done based on MAC addresses, which you can easily spoof if you want.

I wrote up a quick Alfred workflow that shells out from Python to do the real work. Note that if your wifi interface isn’t called en0 this won’t work for you.

The first script shells out to ifconfig to get the current address. Which gives output like the following. We are interested in that ether f4:5c:89:b3:37:e1 line. The first three octets are of a MAC are the Organizationally Unique Identifier (OUI) and we don’t need to change those, what we have is valid already.

en0: flags=8863 mtu 1500
	ether f4:5c:89:b3:37:e1
	inet6 fe80::8da:f24a:a0bb:3b7a%en0 prefixlen 64 secured scopeid 0x4
	inet 192.168.1.126 netmask 0xffffff00 broadcast 192.168.1.255
	nd6 options=201
	media: autoselect
	status: active

Our script captures the OUI, then generates three more octets for the rest of the address, and prints it out.

from subprocess import check_output
from re import compile
from random import randint

MATCHER = compile("\W*ether ([a-f0-9]{2}:[a-f0-9]{2}:[a-f0-9]{2}:[a-f0-9]{2}:[a-f0-9]{2}:[a-f0-9]{2})")
output = check_output(["ifconfig", "en0"])

mac = None

for line in output.split("\n"):
    match = MATCHER.match(line)
    if match is not None:
        mac = match.groups()[0]
        break

prefix = mac[:8]

print "%s:%x:%x:%x" % (prefix, randint(0, 255), randint(0, 255), randint(0, 255))

Next we need to actually set this new random MAC. This is a privileged operation, so it we passed it directly to ifconfig it would error out. Long story short, if we want a nice authorization dialog we have to pass through applescript, russian nesting doll style.

osascript -e  "do shell script \"sudo ifconfig en0 ether {query} >/dev/null;\" with administrator privileges"

I also added a way to reset it to the hardware value. The networksetup command handily has that for the taking. We just shell out, capture it and pass it through to ifconfig again.

from subprocess import check_output
from re import compile

MATCHER = compile("Ethernet Address: ([a-f0-9]{2}:[a-f0-9]{2}:[a-f0-9]{2}:[a-f0-9]{2}:[a-f0-9]{2}:[a-f0-9]{2})")
output = check_output(["networksetup", "-getmacaddress", "en0"])
match = MATCHER.match(output)
print match.groups()[0]

You can download this workflow, comments and improvements appreciated.

ಠ_ಠ Keyboard Button

The other day I was looking at keyboard stuff and decided to order some arrow keycaps for my keyboard. They also had one with the look of disapproval face on it, so I bought that too.

I popped it onto my Print Screen key, which maps to F13 in OS X, then I wrote an Automator service to copy/paste ಠ_ಠ when F13 was pressed.

on run {input, parameters}
	set the clipboard to "ಠ_ಠ"
	tell application "System Events"
		key code 9 using {command down}
	end tell
end run

I have never written AppleScript before, so the result was kind of wonky. It worked in some inputs, but not in others.

Then, Alex pointed out that Alfred workflows can be triggered by global hotkeys. What can’t Alfred do?

A quick workflow later and my ಠ_ಠ key was working like a dream.

You can grab the workflow here, if you want. I bet you could figure it out for yourself too though.

Password Generator Alfred Workflow

I love pwgen for passwords. They are simple and strong, pharmacy but it can be a pain to kick over to the terminal whenever I need one.

So, mind I made a super simple Alfred Workflow for this.

Basically, you type in “pw”, “pwgen” or “password” and it will generate and copy a 40 character password into your clipboard/open app.

You can use the “secure” option to generate stronger, less memorable passwords, and you can pass a length option as well.

Download it here: pwgen.alfredworkflow

Manage Unblock-Us on OS X

Sometimes you need to pretend to be in another country.

VPN’s are great for this, but one novel approach is Unblock-Us which changes the location of your DNS server, instead. You use your IP, but you make DNS requests against in-country DNS servers, thus directing you to the application servers supporting that country. There is no anonymity, but you don’t have to worry about bandwidth caps, and it’s worked for every service I’ve tried it on.

I use this when I need to access video that is region limited. However, changing your DNS servers through the Mac settings app is a pain when you have to do it over and over again. On Windows they have an app to download which can manage the change for you.

So what I did on my Mac was create a script to use the built in networksetup command to change my DNS as needed.

networksetup -setdnsservers "Wi-Fi" 208.122.23.23 208.122.23.22

And one to un-set it.

networksetup -setdnsservers "Wi-Fi" "Empty"

To top it off, I built a simple Alfred workflow, making it even quicker and cleaner.

You can download that here: Unblock-Us Alfred Workflow.

Note that if you are using a wired network interface, you’ll need to change the service name from “Wi-Fi” to, well, whatever it is you are using.