insufficient permissions to change MAC address

Question

I am attempting to change the MAC address of the Wi-Fi hardware of a laptop. When I attempt to change the MAC address using macchanger, I encounter an error:

>sudo service network-manager stop
>sudo macchanger --mac 28:27:c4:f6:ca:a5 wlp4s0
Current MAC:   28:27:c4:f6:ca:a5 (unknown)
Permanent MAC: 5a:ef:56:3d:dd:7e (Intel Corporate)
[ERROR] Could not change MAC: interface up or insufficient permissions: Device or resource busy

Here, the default MAC address of the hardware is 5a:ef:56:3d:dd:7e and the MAC address to which it should be changed is 28:27:c4:f6:ca:a5. How should I approach this error?

Solution

On Kubuntu 14.10 This page has a procedure that works. As root:

service network-manager stop; sleep 5 
ifconfig wlan0 down
macchanger -b -a wlan0; sleep 5 
ifconfig wlan0 up; sleep 5
service network-manager start

The sleeps may not be necessary, but that's what worked. Macchanger is in the repos. My attempts using ifconfig or ip link appeared to take but did not survive connecting to a network, because I didn't stop Network Manager. The burnt in MAC was reasserted.

This also works:

service network-manager stop; sleep 5
ifconfig wlan0 down; ifconfig wlan0 hw ether F8:27:93:01:02:03
ifconfig wlan0 up; sleep 5; 
service network-manager start; sleep 5;

I have a feeling there are some little gotchas lurking:

• In the Network Manager gui, clear the 'Restrict to Device:' field. Also clear the 'Random' field.

• Use a MAC with a recognised vendor prefix, easily found on Goog. Many routers can tell the difference. It also avoids any snafu with the 'locally administered' bit, WTH that is.

• Start from a clean state, regarding the ifup & ifdown commands. They only keep a record of changes they have made & can be inconsistent
  with the true network state ( And no: I have no idea what I'm talking about regarding these)

Easy. Once you know how.

Comments

[iñaki murillo]

try deactivating the interface: sudo ifconfig wlp4s0 down

[ssi-anik]

first command snippet worked for me. had to use sudo.