What format must a valid MAC address have?

[chrstrbrts]

Hello,

It occurred to me recently that not every 12 digit hex number is a valid MAC address.

If I try to change my MAC address through my OS and enter in any random 12 digit hex value, I usually get an error.

Some numbers do work; others don't.

So I'm wondering if anyone knows what the proper format is supposed to be for a valid MAC address for ethernet adapters and wireless adapters?

Thanks.

 

[sdifox]

https://en.m.wikipedia.org/wiki/MAC_address

 

[JackMDS]

What does it matter what the MAC is?

Unless you plan on some illegal Activities!

 

[chrstrbrts]

What does it matter what the MAC is?

Unless you plan on some illegal Activities!

Haha...not at all.

Simply interested in knowing everything about computers.

Thanks for your help, guys!

 

[Harrod]

It can be anywhere in the range of 00:00:00:00:00:00:00:00 to FF:FF:FF:FF:FF:FF:FF:FF, I'm pretty sure that there are some reserved ones out there that would cause problems if you hard set your mac address to one of those addresses though. I don't really know that changing a mac address would really allow you to get away with doing anything. It's kind of like if your downloading something on your own network, the ISP is still going to send you a letter, there is nothing you can tell them that they haven't heard 100 times before.

I work for an ISP, one time I saw the following mac address arped up in one of our routers that is used to terminate DSL customers. It was 00:00E:AD:BE:EF, I got a laugh out of it.

Edit: the MAC spelled out 0000DEADBEEF

Here is a link to the reserved ones.

http://www.iana.org/assignments/ethernet-numbers/ethernet-numbers.xhtml

 

[Ichinisan]

Here is a link to the reserved ones.

http://www.iana.org/assignments/ethernet-numbers/ethernet-numbers.xhtml

At the bottom of that page:

"mailto:steven.knight&ascend.com"

Is that valid somehow?