Locally Administered MAC Address

Locally Administered MAC Address

The Locally Administered MAC Address is used to override the “burned-in” address of network interface cards (NICs). The Locally Administered MAC Address is a user-defined MAC address that is used in place of the MAC address originally assigned to the network adapter. Every adapter in the network must have its own unique MAC address. This locally administered address consists of a 12-digit hexadecimal number.

The appropriate assigned ranges and exceptions for the locally administered address include the following:

The range is 00:00:00:00:00:01 to FF:FF:FF:FF:FF:FD.
Do not use a multicast address (least significant bit of the high byte = 1).
Do not use all 0s or all F’s.

Creating An Access Point With A Locally Administered MAC Address

Using airbase-ng we can create an Access Point with a locally administered MAC address.

root@bt:~# airbase-ng -e “SSID” -a 00:00:00:00:00:01 wlan0
For information, no action required: Using gettimeofday() instead of /dev/rtc
16:37:27 Created tap interface at0
16:37:27 Trying to set MTU on at0 to 1500
16:37:27 Access Point with BSSID 00:00:00:00:00:01 started.

Tools Used To Create Virtual Access Point

BackTrack 4 beta VM Image
Netgear WG111US Wireless G Usb Adapter

One Reply to “Locally Administered MAC Address”

  1. You might want to think about making sure that you also turn on the bit in the MAC address that indicates it is locally administered. This is the second least significant bit in the first byte. In your example, you are using an address that indicates its is globally unique with an OUI that has been assigned to Xerox (i.e., only Xerox should be allowed to assign that MAC address). If you were to modify the address to 02:00:00:00:00:01, then you are not stomping on someone else’s legitimate use of a paid commodity (the OUI), and you also signify that the address is not globally unique.

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