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Author Topic: Looks like we have clones that look real  (Read 11202 times)
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California
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Speaking of suckers, I bought a cheap ethernet shield [mainly as an experiment to
see what I'd get], and it doesn't have a MAC number marked on it.

Even an authentic ethernet shield poses some questions in the MAC address world.  The first three octants indicate the vendor and an authentic has a sticker that is a MAC address (0xDE:0xAD:0xBE:0xEF:0xFE:0xED) registered to Gheo Sa in Switzerland.  I would bet that EVERYONE with an authentic Arduino Shield has that same MAC address sticker on the back.  It is an Italian computer consultancy outfit that I fail to find the connection with Arduino. 

Essentially, the assigned MAC means nothing concerning the hardware.  The MAC is not written to any of the chips and as long as they are unique in a network, they will work just fine.  The MAC would need to be registered if you attempt to operate on the internet like an internet modem etc.  Since, you would be writing the code, you would assign the MAC based on the first three octants that were registered to you and then serialize the next three octants.


---EDIT: Spelling...
« Last Edit: April 01, 2013, 12:33:41 am by spcomputing » Logged


the land of sun+snow
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Essentially, the assigned MAC means nothing concerning the hardware.  The MAC is not written to an of the chips and as long as they are unique in a network, they will work just fine.
Thanks, I had assumed MAC was written into the chips [eeproms].
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Essentially, the assigned MAC means nothing concerning the hardware.  The MAC is not written to an of the chips and as long as they are unique in a network, they will work just fine.
Thanks, I had assumed MAC was written into the chips [eeproms].

after reaserching this that's right you need to burn the mac to the chip

best way to do this cheaply is get an old NIC PCI card and get the mac from that and burn that address to it

then throw away the old PCI card that way you will have a unique address aswell
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Valencia, Spain
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Essentially, the assigned MAC means nothing concerning the hardware.  The MAC is not written to an of the chips and as long as they are unique in a network, they will work just fine.
Thanks, I had assumed MAC was written into the chips [eeproms].

after reaserching this that's right you need to burn the mac to the chip

What chip? The W5100 chip (used on the official Arduino Ethernet) has no way to store a MAC. You have to supply one in your sketch.
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the land of sun+snow
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Even an authentic ethernet shield poses some questions in the MAC address world.  The first three octants indicate the vendor and an authentic has a sticker that is a MAC address (0xDE:0xAD:0xBE:0xEF:0xFE:0xED) registered to Gheo Sa in Switzerland.
This is in line with my previous comment about lack of support and documentation.
It seems the clone maker of my ethernet shield hasn't registered its products, simply
soldered chips to a cloned board and put it in the mail.
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California
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Even an authentic ethernet shield poses some questions in the MAC address world.  The first three octants indicate the vendor and an authentic has a sticker that is a MAC address (0xDE:0xAD:0xBE:0xEF:0xFE:0xED) registered to Gheo Sa in Switzerland.
This is in line with my previous comment about lack of support and documentation.
It seems the clone maker of my ethernet shield hasn't registered its products, simply
soldered chips to a cloned board and put it in the mail.

Just remember, if you have a project that requires two or more authentic Arduino Ethernet Shields on the same LAN, the sticker on the back will still have the same MAC, so you are going to have to increment in the sketch them to make them unique.  Since these devices are projects/prototypes, the responsibility of registering the MAC would be on the final system manufacturer (you, me, etc) not on the board manufacturer (Arduino, clone maker, etc).

Tom Igoe seems to use a "testing" type MAC in the Twitter sketch of 0x00:0xAA:0xBB:0xCC:0xDE:0x01 that is not registered and ready to increment.
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the land of sun+snow
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Just remember, if you have a project that requires two or more authentic Arduino Ethernet Shields on the same LAN, the sticker on the back will still have the same MAC,
Another new piece of information. So, you're saying that every "official" Arduino
ethernet shield will have the same MAC number - at least if coming from the same
manufacturer? Bummer.

Also, my plan was not to be a final manufacturer on this thing, but to use it ultimately
on my home network to get to the internet via my router and cable-internet modem
[not that I currently know how to do all of this].
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Just remember, if you have a project that requires two or more authentic Arduino Ethernet Shields on the same LAN, the sticker on the back will still have the same MAC,
Another new piece of information. So, you're saying that every "official" Arduino ethernet shield will have the same MAC number - at least if coming from the same manufacturer? Bummer.

I would like proof.  Do either of you have two (or more) authentic Arduino Ethernet Shields with MAC stickers?
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I am just betting on it since I am not buying another "official" Ethernet anytime soon.  I was rather shocked when I got my Ethernet Shield and opened up the ChatServer and my unique, one of a kind MAC address was already entered for me.  Only two possibilities, I somehow got David Millis or Tom Igoe's Ethernet Shield or the MAC address is just a safe resting place for developers (especially the high serials of EF:FE:ED).

If anyone wish to verify their "official" Arduino Ethernet MAC, I would love to confirm my theory.

Anyhow, if you run inside you home network, you will be fine with any unique MAC as long as you are behind your router.  You will just need to open a port on the router to access it from the outside or get a home server up for Arduino management.  Arduserver is a good starting place
http://arduserver.com/

@Coding Badly
What does your Ethernet Shield MAC sticker have on it?  Mine has 0xDE:0xAD:0xBE:0xEF:0xFE:0xED which is identical to the ChatServer sketch.
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I have an official Ethernet shield with 90A2:da00:822e, and an official Arduino Ethernet with 90a2:da00:6173
(those are the stickers.  As others have said, the chipsets involved do not have any embedded MAC address at all, so it's up to you to have your sketch assign unique MAC addresses, perhaps based on the "serial number" that is in EEPROM.  If they're still doing that.)

Note that the first byte of the MAC address contains two magic bits.  Bit 0 indicates whether the address is a unicast or a multicast.
And bit 1 indicates whether the address is "locally administered" or "globally unique."  Locally administered addresses used to be used for things like the algorithmically derived ethernet addresses of DECNet hosts (from the DECNet Node/Net parameters, you know.)  Using any "locally administered" mac address on your local network is probably pretty safe.  You can use the old DECNet prefix if your net is DEC-Free (AA-00-04), or perhaps something like 66:66:00:a:b:c (where a.b.c is the arduino serial number) if you want the nodes to stand out...  (Alas, "UNO" and "INO" don't work.  "ARD" might.  But nothing displays mac addresses in ascii, anyway.)
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Just remember, if you have a project that requires two or more authentic Arduino Ethernet Shields on the same LAN, the sticker on the back will still have the same MAC,
Another new piece of information. So, you're saying that every "official" Arduino ethernet shield will have the same MAC number - at least if coming from the same manufacturer? Bummer.

I would like proof.  Do either of you have two (or more) authentic Arduino Ethernet Shields with MAC stickers?
Me too. For my part, I'm just asking questions and trying to find out what's going on
here. As mentioned, my cheap clone came with no MAC number on it.
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What does your Ethernet Shield MAC sticker have on it?

Don't have one.  I just find it odd that the Arduino folks would go to the expense of including a MAC sticker but fail to provide some level of uniqueness.  Especially given the fact that the parent company (Gheo) has a vendor ID.

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Mine has 0xDE:0xAD:0xBE:0xEF:0xFE:0xED which is identical to the ChatServer sketch.

How long ago did you purchase the adapter?

Quote
0xDE...

Assuming I'm reading the Wikipedia article correctly (and the article is correct) that would be a locally administered / unicast address.

90A2:da00:822e  ... gobal / unicast
90a2:da00:6173  ... global / unicast

http://standards.ieee.org/cgi-bin/ouisearch?gheo
90-A2-DA ... GHEO SA ... definitely Gheo's vendor ID
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I have an official Ethernet shield with 90A2:da00:822e, and an official Arduino Ethernet with 90a2:da00:6173
And I have a 2nd shield with :821a at the end.  All three were acquired in Sep 2011.

Gheo and Arduino appear relatively intimately related.  Gheo owns the "tinkerit" trademark, for example.
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Essentially, the assigned MAC means nothing concerning the hardware.  The MAC is not written to an of the chips and as long as they are unique in a network, they will work just fine.
Thanks, I had assumed MAC was written into the chips [eeproms].

after reaserching this that's right you need to burn the mac to the chip

What chip? The W5100 chip (used on the official Arduino Ethernet) has no way to store a MAC. You have to supply one in your sketch.


I was referring to Ethernet IC ENC28J60

here is the info I got

Quote
the ENC28J60 does not have a pre-assigned MAC address, you
have to write it on MAADR0 to MAADR5 registers. If you are
using the MCHP TCP/IP stack, the MAC address is defined in
StackTsk.h and is sent to the ENC during the registers setup
on MacInit(). Microchip has a OUI (first 3 bytes of macaddr)
registered with IEEE = 00-04-a3.
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The first three octants indicate the vendor and an authentic has a sticker that is a MAC address (0xDE:0xAD:0xBE:0xEF:0xFE:0xED) registered to Gheo Sa in Switzerland.

"DEAD BEEF FEED" is commonly used in programming where an arbitrary 12 digit hex number is needed, in the same spirit as the variable names "foo" and "bar".  It comes up a lot in Arduino Ethernet demonstration code where the MAC address is defined in software.  For home networks it's usually fine, but don't count on it being unique.

As an alternative whimsical HEX number I offer "DEAF BABE CAFE", or the more sophisticated "BEADED FACADE".  Any more?
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