Byte Order or MAC Address on Ethernet and WiFi Shields

Are the byte order for the WiFi shield and the Ethernet shield actually reversed, or are the examples for the Ethernet Shield wrong?

I can't figure out what the Ethernet libraries (or more specfically, the W5100 library) is doing with the MAC data that is passed to it. It uses a function called writeSHAR that I can't seem to find anywhere else, so I don't know where it's getting written to.

The WiFi libraries return the MAC bytes in MSByte last, but all the examples that I've seen have you enter the MAC MSByte first.

Which is the most significant byte in a MAC address? That does not exist because because the MAC address is not a big number (although you can see it as that) but a sequence of 6 bytes. writeSHAR write these 6 bytes into the SHAR register of the WizNet5100 chip. Can you please explain why you think the examples should be wrong? Show the code that misbehaves in your opinion.

I'm not saying that the examples are wrong, I'm asking if they are wrong or if they the MAC byte arrays are different between the Ethernet and the WiFi shield's libraries.

I know that the MAC is not one big number, but I thought that that would be an easy way to describe the order.

My question basically, boils down to:

TL;DR: For the Ethernet Shield, is the byte with the lowest index the right most or the left most byte in the MAC?

The WiFi is definitely lowest index is right-most, but I can't find any thing official that state it for the Ethernet Shield, but in some of the example code I've found it is used as the left-most having the lowest index. I would think that they would be setup the same, so I wanted to check to see if any one knew for sure.

EDIT: I'm trying to use the MAC as an identifier for each device and I'd like to be correctly handling the Ethernet shield MAC. I know it most likely won't make a difference on the network if the MAC is reversed, but best practices and all...

Just realized that I could do an arping on the arduino and read the on-network mac.

Then answer is yes, they are reversed.

The Ethernet MAC Address is entered with the left-most byte having the lowest index. The WiFi shield returns the MAC adress with the right-most byte having the lowest index.

The Ethernet MAC Address is entered with the left-most byte having the lowest index. The WiFi shield returns the MAC adress with the right-most byte having the lowest index.

In this case the Ethernet shield/library does it correctly while the Wifi shield/library is a bit odd.