MAC stands for (Media Access Control)
and stands for the computer physical address in LAN networks.
Ethernet MAC is a six byte number, usually expressed as a twelve
digit hexadecimal number.
IPs are translated to Mac via a protocol called ARP (Address
Resolution Protocol).
Let's say Computer with IP 10.10.10.1 wants to send information to
another system on the LAN with an IP of 10.10.10.2.
10.10.10.1 will first send broadcast to all stations on the LAN
asking who has the address of 10.10.10.2.
Then the box possessing 10.10.10.2 will respond to 10.10.10.2 with
it's MAC address which would be temporary stored
in 10.10.10.2's ARP's table in order to make 10.10.10.1 recognize
10.10.10.2 later on.
Host 1 (10.10.10.1): Hello everyone on the LAN (FF:FF:FF:FF:FF:FF),
who has the IP 10.10.10.2? My MAC is DE:AB:BE:EF:FF:FE so you can
respond back to me. Host 2 (10.10.10.2): Hello DE:AB:BE:EF:FF:FE, I
have IP 10.10.10.2 and my MAC address is 1C:43:B6:F8:9B:1E so you
can send your IP packets to me.
There are a plenty of reasons that might force to wish for changing
your mac. Though I'll mention only one
1. To get across MAC filtering set on a router. Or in other words
to bee able to access your internet with all your computers at home
(don't try them simultaneously!). For example recently a cousin of
mine bought a second notebook for her daughter.
They desired to be able to access the internet with both the PCs. I
contacted the ISP with a request to add me a second MAC address,
just to find that this wasn't possible with this exact ISP.
Their computer ran dual boot install of a GNU/Linux system as well
as Windows Vista, thus I needed to change their existing MAC
address in both Windows and Linux
Here is how I achieved that:
1. In Linux
Really simple:
/sbin/ifconfig eth0 hw ether 00:00:00:00:00:00 (substitute here with your desired MAC)
/sbin/ifconfig eth0 up
2. On BSD
/sbin/ifconfig xl0 link 00:00:00:AA:AA:AB (subst with MAC here), xl0 is your interface name
/sbin/ifconfig xl0 up
3. In Windows XP
There are a couple of ways to go in Windows. The hardest way is to
use regedit and to look and substitute some obscure values.
Another a bit easier way is to use either
MacMakeUp
,
Smac or
EtherChange
The classic way to change Mac in Windows XP is:
Go to Start->Settings->Control Panel and double click on Network and Dial-up Connections
a) Right click on the NIC you want to change the MAC address and click on properties.
b) Under "General" tab, click on the "Configure" button
c) Click on "Advanced" tab
d) Under "Property section", you should see an item called "Network Address" or "Locally Administered Address", click on it.
e) On the right side, under "Value", type in the New MAC address you want to assign to your NIC. Usually this value is entered without the "-" between the MAC address numbers.
f) Goto command prompt and type in "ipconfig /all" or "net config rdr" to verify the changes are applied.
4. In Windows Vista
Go to Control Panel -> Network Connections -> Properties (on Connection using ...) Configure -> Advanced -> Network Address (Then type your MAC Here)
All the credits for this post go to the article
Changing
Your MAC Address In Window XP/Vista, Linux And Mac OS X which
explains what you read above even more thoroughly.
Most of the information here is originally found in the above
article.