2012-11-30

As you probably know every ethernet card has a unique MAC address, programmed by the manufacturer, which helps ISP to identify any card connected to the network. But sometimes we need to change that address, especially when working with a laptop and we often have to connect to different networks. There are also internet service providers who bind their service to a specific MAC address and when a user change its network card or install a router, the service may become unavailable. Changing the MAC address of the new card will solve the problem. There are programs specifically designed for this purpose, but what happens if we don’t have such programs and can not establish an Internet connection to download them?
In this short guide I will try to explain how to change your ethernet card’s MAC address without need of any additional programs.
Some manufacturers of ethernet cards provide drivers with built-in option  allowing you to change the Mac address. To use this option do the following:

1. Go to Start > Control panel > Network and Internet connections , then right click on the that network connection whose network card’s MAC address  you want to change and click Properties.
2. In the General tab, click on the Configure button.
3. Then click on the Advanced tab.
4.In the Property section, you have to see an option saying Network Address or Locally Administered Address. Select it and change the radio button to Value ( Not present means that your network card will use the default MAC address programmed by the manufacturer ).

5. Now type in a new MAC address and click OK.
6. Restart the computer.
7. To make sure that the change is successful go to command prompt ( Start > Run, type in cmd and click OK )  then type in  ipconfig /all.
As you can see the above method is very convenient but not all network cards offer such an option. For example, Broadcom 440x 10/100 ( used in Dell Inspiron 1501 laptops ) does not allow to change its MAC address through the Properties window. In such cases the following method will solve the problem.
1. Go to Start > Run and type regedt32 in the box to start the registry editor.
2. Go to the following registry key:  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002BE10318} and double click on it to expand the tree.
3. Now you can see the subkeys starting with 0000, then 0001, 0002, 0003, 0004 and so on. Each of them represents  particular network adapter.
4. Go through each subkey and look for DriverDesc keyword, that matches the network card you want to change the MAC address.
5. Look for a string value named “NetworkAddress”, right click on it and  select Modify. Then enter a new MAC address in its value data box.  If the value  “NetworkAddress” does not exist, then create one with right click on the subkey ( for example 0008 ), then select New > String Value, name the new value as NetworkAddress and repeat the above step.

6. You must restart your computer for the change to take effect.

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