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Topic: Looks like we have clones that look real (Read 11 times) previous topic - next topic

spcomputing


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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.

oric_dan

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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].

Coding Badly

Quote
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?

spcomputing

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.

westfw

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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