Thread: Need some info on MAC address

I've tried to learn more about MAC addresses, but somehow I can't get it clearly. From what I know, it uniquely identifies a computer. Earlier I used to think only the IP address can be used to trace you, and that too the other party will have to contact your ISP. Now this MAC address, is it something which others can come to know easily. Like you send an email to someone, does that capture the MAC address? Is it only your ISP who knows this address or is it commonly broadcast out to the rest of the world?

There are tutorials and little apps available on the net to spoof the MAC address - is there any need to do this? What happens if you don't, and if you do change the address, will the ISP automatically detect the new address or will it cause headaches?

Like I said earlier, I'm a total noob in this department.

As far as i know, mac id is related to modem. And outsiders, other than your isp (in my case BSNL) will not be able to know your mac id. If you post any complaints of your usage, they check the mac id in usage details and confirm that it was you who used it. Please correct me if i am wrong.

Hydraheaded, you have started an interesting topic.

As you said, MAC address is very specific to a network card and not to computer. no other network card in the world have same MAC address of yours. but pity thing is we can do "MAC Spoofing", a kind of logically changing MAC address of your n/w card and this is mainly used to hide one’s identity for malicious activity.

if you change your MAC, you must be able to use internet unless any blocks are defined (in Antivirus or firewall)

In short, your modem does all job to route traffic between ISP and your laptop; so only your modem will have your MAC registered and not your ISP. ISP uses modem's MAC instead. But I believe, ISP keep backup of router/modem tables like routing table for forensics.