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I have changed my MAC address in my Linux machine using ifconfig. Now the problem is I have not saved my original MAC address. I want to restore it without rebooting.

Is there a way to do it?

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Any reason no to reboot? – new123456 Jun 16 '11 at 15:12
    
Running half a dozen applications. Dont want to close them. – narayanpatra Jun 16 '11 at 15:14
1  
Run this?: sudo ifdown interface && sudo ifup interface Or maybe: sudo /etc/init.d/networking restart – evan.bovie Jun 16 '11 at 15:25
    
@emb : did not work. – narayanpatra Jun 16 '11 at 15:30

You can get your vendor-specified hardware MAC address using ethtool:

ethtool -P eth0

To reset the MAC address to this value, you can do something like:

sudo ifconfig eth0 hw ether $(ethtool -P eth0 | awk '{print $3}')
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Assuming eth1:

grep "eth1" /var/log/*log | egrep "([0-9a-fA-F]{2}:){5}"

could find something in the logs {daemon,kern,syslog}.log on my system.

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[rooted] assuming wlan0

...(to find driver)
airmon-ng | awk '/wlan0/ {print $4}' ...or

airmon-ng | awk '/wlan0/ {print $3}' ...or just

airmon-ng ..and look under 'driver'

...(to restart driver)
ifconfig wlan0 down

modprobe -r rt2800usb <=Replace (rt2800usb) with your driver

modprobe rt2800usb <=Replace (rt2800usb) with your driver

ifconfig wlan0 up

This is how I do it. I made a script for this and use it with a couple of my programs. If that's the route you take, put a 'time.sleep(3)' {or whatever sleep command} before bringing the interface back up.

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Maybe try removing then installing the module again?

sudo rmmod <NICmodule>
sudo insmod <NICmodule> 

Or maybe dropping the interface and bringing it back up?

sudo ifdown <interface> && sudo ifup <interface>
share|improve this answer
    
can you elaborate the first method. The second one did not work. – narayanpatra Jun 16 '11 at 15:31
    
The <NICmodule> would be what ever kernel module the NIC is using. e.g. e1000 You can see what you have with this guide. – evan.bovie Jun 16 '11 at 15:36
    
Do you know what module your network card uses? This will just remove the module and then put it back (hopefully with the right MAC) – sealz Jun 16 '11 at 15:38
    
@narayanpatra Did you replace interface with what you use to access the internet? In most cases it's eth0 – paradd0x Jun 16 '11 at 15:39
    
@thiago : Ya, i did that. – narayanpatra Jun 16 '11 at 15:46

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