Wednesday, August 29, 2007

Changing MAC Address

In a network where IP Address is provided by DHCP mode, how will you identify a particular computer? The answer to this is MAC (Media Access Control) Address of an ethernet card. Every ethernet card is burnt with a MAC address. But, the MAC address can be changed. Here is how to:

ifconfig ethx down
where ethx is the interface. This command is to deactivate the ethernet card.

ifconfig ethx hw ether xx:xx:xx:xx:xx:xx
where xx:xx:xx:xx:xx:xx is the 12 digit hex address which you want the address of your ethernet card to be.

ifconfig ethx up
This command is to activate the ethernet card.

And you are there.

There are softwares like macchanger which can also be used to change the MAC address. They do not do anything different from the previous method expect allowing you change to MAC address from particular vendor. So, the above method is advisible rather than using macchanger.

But your MAC address gets restored once you restart your computer. Now how to this permanently. Well, there are different methods for this. You can write a script and add to your run-level to load it when computer boots. But I prefer a more easy and convenient method of editing the file /etc/network/interfaces.
In the above file, you will see line like
auto ethx
Below this line add the following line:
hwaddress ether xx:xx:xx:xx:xx:xx

N.B. : You will need root permissions to do the above tasks.

The above examples are given with reference to Kubuntu-7.04. The methods described above should work with others Linux distros as well.

Saturday, August 25, 2007

Acid Test for Web browsers

Have u ever wondered if your web-browser follows the agreed standards. You can have acid test for your web-browser at the following link:
This page links to a test script for checking whether your web browser confronts to the setup standard. I tested it on Mozilla Firefox and Konqueror.
I was pretty sure that Firefox will pass the acid test but it badly disappointed me. It didn't properly support the transparency and other features. Well, the page specifically mentioned that Browser had to be in default setting. I guess mine is.
With very little expectations, I tested it on Konqueror. Guess what, it rendered it perfectly (at least what it seemed at first sight!). It was something unbelievable. Now I guess I have answers why Apple chose to base its Safari on Konqueror. But with some more efforts I could find some problem with Konqueror also. Certain portion of image moved when scrolled while other portion was static. That is it had problem with fixed-positioning. Moreover, re-sizing of the window distorted the image.
I read the Opera performance on the link provided above. What I figured out was that Opera also have same faults as Konqueror.

I wish I could test the other web-browsers but I had only these two installed.

Does your browser pass the acid-test? Do comment.