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I'm changing my MAC address for my MacBook's AirPort because the list of devices my router can hold (only 25!) is full.

Therefore, I used ifconfig and the tool ChangeMac. Everytime I restart the Mac or return from sleep mode, I have to change the MAC address again.

How can I permanently change it?

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up vote 3 down vote accepted

I don't think that is possible, since the MAC is programmed directly into the Network Controller and OSX doesn't have a way to change it. However, you could run ifconfig when you boot up using a shell script in your StartupItems. Here is a thread on Mac Rumors describing that process:

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Thanks, that was what I was looking for. – Hedge Jun 14 '11 at 14:35

You can't permanently change the MAC address on a card. It is burned into the hardware chip. At most you might be able to have the OS do it for you each time it wakes up, as windows will with the registry, but I don't know off the top of my head how to do that on OS X.

However, this highlights a bigger issue. You should not have multiple devices on a network with the same MAC address. You should replace an entry in the table with the MAC address of the wifi-adapter.

I'm not sure of any routers that actually limit the number of MACs you can have on a wireless network. Are you talking about MAC-address filtering? If that's the case, then I wouldn't really bother with the filtering. You yourself are proving just how easy it is to circumvent. It adds a single layer of complexity, but no additional security (anyone trying to break into the wireless network is going to listen for a MAC that the router responds to and clone that MAC as the first thing they do).

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Yes I am talking about Mac-adress filtering. I only use the new Mac with that Mac-adress and will as soon as possible replace the old one. (A colleague who is currently ill is the only one knowing the router-password). – Hedge Jun 14 '11 at 14:31
I'd honestly just dump the filtering as soon as you can, then. The only time it is going to actually slow someone down is if they're trying to break into the network while there is absolutely no device communicating with the network, which would require them to all be off or out of range. If you could, I'd just ask the colleague for the password, but I'd also hope he doesn't give it to you. (You should never, ever ever ever ever EVER give out your password. To anyone. In any situation) – Darth Android Jun 14 '11 at 14:35
  1. Install Virtualbox
  2. Install a Linux in Virtualbox
  3. Configure a different MAC address for each saved connection easily within the graphic user interface
  4. Connect to the Internet with the Linux inside your Mac.

A better solution is to use LINUX natively, with dual boot in your MAChine.

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Solution to everything: Install linux :) – Michael May 17 '13 at 3:17

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