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Suppose we know that MAC address A belongs to a certain device (say an iPhone 5), and MAC address B also belongs to an iPhone 5. If we have a MAC address C which is in between A and B, does this guarantee that C is an iPhone 5 or could it be any Apple product?

EDIT: Suppose they all have the same 3 byte prefix, e.g.:

A=44:2A:60:01:01:01
B=44:2A:60:21:AA:F4
C=44:2A:60:01:02:03
makerofthings7
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sciencectn
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1 Answers1

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It could be any product, not just any Apple product.

The first 3 bytes (24 bits) of the MAC address identify the vendor of the NIC (Network Interface Card). If Apple owns the blocks 00:00:01 and 00:00:03, then MAC-address 00:00:02:00:00:01 could belong to Cisco as well as any other vendor.

And besides, almost every NIC allows changing (spoofing) the MAC-address. They are not really that reliable, especially when people know you are trying to identify devices based on their MAC-address.

Edit: In reply to your edit, yes those would all be from the same NIC vendor, given that the user has not changed his MAC-address manually.

Luc
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    Vendor in this case should be NIC vendor, as Apple will buy their NICs. – Manuel Faux Nov 19 '12 at 10:29
  • @ManuelFaux You're right! Edited post accordingly. – Luc Nov 19 '12 at 11:49
  • @ManuelFaux In the most common cases you would be right. But I have seen a vendor deliver Ethernet chips without assigned MAC addresses, and you had to get your own. – kasperd Jan 13 '17 at 08:19