Ordered 5 single board computer ref. design, all are same MAC addr, what to do?

Every ethernet interface MAC address ever made is supposed to be unique. A few years ago a NIC card manufacturer screwed up and made a bunch of identical cards and it made the trade press.

Contact the people you bought them from.

If it's for use on your own network, you can assign them private use MAC addresses, similar to private use IP addresses. IEEE reserves addresses starting with "AC-DE-48" hex for this use.

Otherwise, I'm not sure what the process is. The board manufacturer might know.

---Scott.

The requirement is only that it be unique per broadcast domain. It so happens that the easiest way to ensure that without hastle is to make them globally unique.

If I recall correctly, SunOS uses the same MAC for all NICs in a given machine.

VMS sets the MAC at runtime, too. So does any box functioning as a transparent bridge. The *hardware* is supposed to gave a globaly unique address with the Manufacturers's space assigned by the IEEE, or whoever does it these days, and a serial number assigned by the hardware manufacturer.

It's possible that the company that made this prototype didn't burn an IEEE code becuase it's a *prototype* and whoever mass produces the design is supposed to get their own from the IEEE.

Many drivers allow you to set a unique MAC address through software. If it can't be done, you'll have to complain to the manufacturer, sounds like they messed up.

Well, this is for private LAN use only, can I set any private MAC addr?. Please suggest me.

Indeed it does. Which used to wreak havoc with some novell stuff they had to interoperate with at $two-dayjobs-ago.

The first "layer 3 switch" I ever bought was a 3Com Corebuilder 3500 in '98 or '99. It left me asking the same question as Rick in another thread: "Layer 3 switch? Isn't that a router?"

This silly box doesn't maintain a seperate table of MAC addr -> port mappings for each broadcast domain. When the same MAC appears in multiple VLANs there are problems.

Indeed. That's why I know about the flaw in the 3Com box.

Older Sun equipment didn't have MAC addresses on any Ethernet cards. Then Sun started equipping add-on (SBus hme, maybe others) cards with individual addresses, but those addresses weren't used by default. These days, I think all Sun NICs (onboard or accessory) have their own addresses, but they're still not used by default.

For the OP: Bummer about your single board computers. I'd complain to the manufacturer, see if they couldn't have given you random different addresses with the LAA bit set.

/chris marget

If you can set the MAC then just make some numbers up. They don't get propagated outside the local segemnt.

Don't ship these to customers, though.

Hey, if you just need a few MACs, what's wrong with just going to your junkbin (or electronics surplus), pulling out some old cards with MAC printed on them, rendering them unusable and storing them away, then reusing those MACs?

-- Robert

And driving the system admin nuts when he's trying to track down that "SMC Nic" the no one every bought or installed. :)

I couldn't even get the other official support people to keep me informed about new device installations, let alone the end-users.

Network administrators: people for whom "You don't have to be crazy to work here -- but it helps!" is too sunnily optimistic.

In that case, "eeprom 'local-mac-address?=true'" is your friend.

Been there, done that ;-).

Regards,

Marco.

Al Dykes wrote: (snip)

DECNet sets the MAC address based on the DECNet address, legal according to the standards, though only one protocol can do that (on a given host).

-- glen