How Do I Find My Mac Address?

[ChiangMaiThai]

How Do I Find My Computer's MAC address? (XP). Thanks!

[rio666uk]

start > run

type "cmd" hit enter

you should now see a dos window - at prompt type "ipconfig /all"

your mac address will be defined as "physical address"

[ChiangMaiThai]

start > run

type "cmd" hit enter

you should now see a dos window - at prompt type "ipconfig /all"

your mac address will be defined as "physical address"

<{POST_SNAPBACK}>

Thanks! Can certain websites identify my computer by tracing my MAC address?

[rio666uk]

yes - its possible but unlikely they would, most would trace via IP.

ISPs will often register your internet account using MAC ID, as it cant be changed like an IP address. I use Telewest Broadband here in UK and thats how they do it.

There is no way that i know of to remove the MAC Hardware Address from the Network Card - you would need to remove that network card and replace.

[rio666uk]

just to add...

the remote device (webserver or router) would keep an ARP/RARP table that would be able cross-ref an IP address with a MAC address but its lifespan is fairly short to stop the ARP/RARP tables getting too big.

can i ask why you ask?

[Khun Jean]

A mac address was a good identification of a computer (its network card). Ranges were given to manufacturers to avoid conflicts. On a low level the mac address is used to send data from one computer to the other. Now you find many cards which have a default address stored in programmable chips along with other configuration settings. These can easily be changed with some software.

A mac address access table is often used in wifi hotspots.

Edited September 23, 2005 by Khun Jean

[ChiangMaiThai]

just to add...

the remote device (webserver or router) would keep an ARP/RARP table that would be able cross-ref an IP address with a MAC address but its lifespan is fairly short to stop the ARP/RARP tables getting too big.

can i ask why you ask?

<{POST_SNAPBACK}>

Thanks for all the info. I am curious about internet privacy. I know websites can track users by the IP address, but they know that users often visit via proxies so the IP address can be useless. So I'm curious if they then turn to the MAC address. For instance, if you were suspended from tv.com ( I was not ), if you registered a new account and came in via a proxy, would they still see that you are you since your MAC address is the same?

I found a site selling software that changes the MAC address for $20 by the way.

[think_too_mut]

I found a site selling software that changes the MAC address for $20 by the way.

<{POST_SNAPBACK}>

HP-UX (Unix) comes with a standard tool to change MAC address. I did it on several hundred servers 7 years ago, to make location of problems instantly known within IBM's SNA. Burned in new MAC addresses that reflected the servers' names.

[LivinLOS]

I thought the MAC was a hardware function requiring a firmware rewrite ?? Curious how the HP-UX managed to do that at the OS level..

I know many / most routers can emulate a MAC address..

[think_too_mut]

I thought the MAC was a hardware function requiring a firmware rewrite ?? Curious how the HP-UX managed to do that at the OS level..

I know many / most routers can emulate a MAC address..

<{POST_SNAPBACK}>

HP provided the utility, thru "adm". It was there since HP-UX 10.

The cards are still operating under those changed MAC addresses.

Edit: yes, it was hardware rewrite, how else could I do it?

Sun had that too.

Edited September 23, 2005 by think_too_mut

[LivinLOS]

Ahh ok so it was a FW update tool for a specific hardware closed box system..

I was trying to visualize a way of an OS generically changing a MAC address on any form of installed NIC..

[AlexBrown]

How Do I Find My Computer's MAC address? (XP). Thanks!

<{POST_SNAPBACK}>

You should try GentleMAC utility. mmm... url like http://www.solarst.com

Best Regards!

[autonomous_unit]

The ethernet MAC address is NOT visible past the first router your traffic encounters. Find a friend with a website who can run ethernet-level traces, and have them log the traffic while you browse the site if you do not believe me.

The MAC address is used locally for addressing different stations on the same LAN, but a router sits at the boundary between multiple such LANs (or other link-layer mechanisms such as DSL, frame-relay, or plain old serial line) and forwards packets between them. When the router forwards your packet, it would include the link-layer addressing needed to get traffic between the router and the next hop in the path, and NOT the link-layer addressing that was required to get the packet between you and the router. The only way your MAC address will be visible to a remote web site is if your browser or some plugin discovers your MAC address and adds it to the web content being exchanged between your browser and the remote site.

Also, most NICs these days handle the MAC just as any other soft register. The firmware may have a default MAC in it, but the OS can set a different MAC whenever it wants (without changing the value in firmware). On Linux, it is trivial to change the MAC address and in fact this is used for some operating modes such as "bonding" where to NICs will be slaved to the same MAC address so that load-balancing can occur over a LAN switch that understands bonding and multi-path addressing.

Now, what is possible is that a LAN operator (fixed or WiFi) could log MAC addresses and what IP address was used with them at what time. A fixed LAN operator could also log things like physical switch port or link numbers, so that the MAC address isn't even necessary to identify a unique location. It is not the remote web sites that know your MAC address, but the local LAN operator can remember it and share it out of band if he likes. Conceivably, one could trace backwards through all this logged data if the different operators decided to cooperate.