Re: DAD question

joel jaeggli <joelja@bogus.com> Wed, 15 August 2012 19:18 UTC

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Date: Wed, 15 Aug 2012 12:18:15 -0700
From: joel jaeggli <joelja@bogus.com>
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To: "Manfredi, Albert E" <albert.e.manfredi@boeing.com>
Subject: Re: DAD question
References: <CALKmEuAqzAsabqs7dMBHHkBvwbAx_UVLgJGJH83-y9wHZKt6FQ@mail.gmail.com> <20120815.125627.74680163.sthaug@nethelp.no> <502B88DC.3060300@gont.com.ar> <20120815.133810.41706030.sthaug@nethelp.no> <B0147C3DD45E42478038FC347CCB65FE02BCFA4C29@XCH-MW-08V.mw.nos.boeing.com>
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On 8/15/12 12:00 PM, Manfredi, Albert E wrote:
> sthaug@nethelp.no wrote:
>
>> Globally unique. The point here is that the Ethernet standards require
>> a globally unique MAC address *per box*, not necessarily per interface.
>> The "Sun way" of storing a MAC address in EEPROM and configuring all
>> network cards with the same MAC address was perfectly compliant, just
>> somewhat unusual.
> But that's not the whole story, right?
>
> The only way this can work is if one assumes that each interface of that box is connected to a different IP subnet. I don't even think Ethernet rules are what matters here. If the box should happen to be dual homed to the same IP subnet, that Sun scheme doesn't work. (I suppose unless only one of the box's interface is active at any given time.
To be clear the employment of that scheme predates existence of routers 
in in small network deployments.

if you need more than one interface on the same subnet you adjust them 
accordingly.
> Bert
>
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