Change MAC address on Intel Mac?

I was running into a few issues trying to spoof my MAC on the command line (on LION) like users above, and I came across this useful post: http://maymay.net/blog/2011/03/29/how-to-spoof-your-mac-address-on-mac-os-x-for- reals/

There's also a tool that you can use to automate the setup directly from System Preferences:

http://www.macspoofer.com

hope this helps!

Hello Kappy,

Why is it not a good idea to change the MAC address?

Thanks Kevin

kevintii wrote:

Hello Kappy,

Why is it not a good idea to change the MAC address?

Thanks Kevin

Because it is intended to be a globally unique identifier of hardware. The MAC address can be changed on modern systems but why? See here for more info http://en.wikipedia.org/wiki/MAC_address

Here are some reasons a person may want to change their MAC address. None of them sound like legitimately valid reasons.

From http://www.irongeek.com/i.php?page=security/changemac

1. To get past MAC address filtering on a router. Valid MAC addresses can be found by sniffing them and then the deviant user could assume the MAC of a valid host. Having two hosts on the same network can cause some network stability problems, but much of the time it's workable. This is one of the reasons why MIC Address filtering on a wireless router is pointless. An attacker can just sniff the MAC address out of the air while in monitor mode and set his WiFi NIC to use it. Interestingly, a lot of hotels use MAC filtering in their "pay to surf" schemes, so this method can be an instant in for cheap skate road warriors.
2. Sniffing other connections on the network. By assuming another host's MAC as their own they may receive packets not meant for them. However, ARP poisoning is generally a better method than MAC spoofing to accomplish this task.
3. So as to keep their burned in MAC address out of IDS and security logs, thus keeping deviant behavior from being connected to their hardware. For example, two of the main things a DHCP server logs when it leases an IP to a client is the MAC address and host name. If you have a wireless router look around on it's web interface for where it logs this info. Luckily there are tools to randomize this information (MadMACs).
4. To pull off a denial of service attack, for instance assuming the MAC of the gateway to a sub net might cause traffic problems. Also, a lot of WiFi routers will lock up if a client tries to connect with the same MAC as the router's BSSID.

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