MAC Identification on WAN VIA NAT?

[nullack]

I know that the WAN IP is accessible to all public traffic.

However If I'm running NAT on my private internal class C IP network, can wan based traffic detect which particular machine with its unique MAC address is actually engaged in the traffic on the wan?

Thanks

 

[Tamarin]

The short answer is no, the WAN cannot tell the MAC address of a host inside your network.

The more detailed answer is, there are several other things that something on the WAN side can look at to identify hosts inside the NAT. Some of them are TCP info (sequence numbers, high port numbers), http browser info, cookies, and applications that generate unique internal ID numbers when talking.

In theory, an ISP shouldn't know if you were NATting. But if they cared, and put in a little effort, they could see if it was happening.

Hope this helps.
Tamarin