Ordered 5 single board computer ref. design, all are same MAC addr, what to do?
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Posted by snertking on February 15, 2006, 11:08 pm
Please log in for more thread options Walter Roberson wrote: >
>>Every ethernet interface MAC address ever made is supposed to be
>>unique. >
> > 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. Indeed it does. Which used to wreak havoc with some novell stuff they had to interoperate with at $two-dayjobs-ago. | |||||||||||||||||||||||||
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Posted by M.C. van den Bovenkamp on February 16, 2006, 2:34 pm
Please log in for more thread options snertking wrote: >> If I recall correctly, SunOS uses the same MAC for all NICs in a given
>> machine. >
> Indeed it does. Which used to wreak havoc with some novell stuff they > had to interoperate with at $two-dayjobs-ago. In that case, "eeprom 'local-mac-address?=true'" is your friend. Been there, done that ;-). Regards, Marco. | |||||||||||||||||||||||||
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Posted by on February 16, 2006, 9:05 am
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Walter Roberson wrote: > >Every ethernet interface MAC address ever made is supposed to be
> >unique. >
> 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. >From a standards point of view, that's true, but not all equipment is
so enlightened.
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. > If I recall correctly, SunOS uses the same MAC for all NICs in a given
> machine. 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 | |||||||||||||||||||||||||
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Posted by Scott W Gifford on February 15, 2006, 11:21 am
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> Ordered 5 single board computer ref. design, all are same MAC addr,
> what to do?, do I have to buy a unique MAC addr?. Please let me know. 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. | |||||||||||||||||||||||||
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Posted by GS on February 15, 2006, 9:01 pm
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Well, this is for private LAN use only, can I set any private MAC addr?. Please suggest me. | |||||||||||||||||||||||||
