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Re: DAD question

Michael Richardson <mcr+ietf@sandelman.ca> Sun, 12 August 2012 16:20 UTC

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From: Michael Richardson <mcr+ietf@sandelman.ca>
To: Bob Hinden <bob.hinden@gmail.com>
Subject: Re: DAD question
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Date: Sun, 12 Aug 2012 12:20:24 -0400
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Cc: "ipv6@ietf.org 6man" <ipv6@ietf.org>, "Fred Baker (fred)" <fred@cisco.com>
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>>>>> "Bob" == Bob Hinden <bob.hinden@gmail.com> writes:
    Bob> True, but the odds of this happening are very low.  I wonder if
    Bob> we have any data on DAD detecting duplicate addresses and their
    Bob> cause. 

In my experience, MAC address duplicates are almost always the result of
too-true copy&paste'ing of virtual machine configurations :-)
(You want to duplicate the virtual machine in order to try an upgrade...)

    Bob> For example, has any seen any actual duplicate MAC addresses?
    Bob> It would be good to collect some data. 

if you remove 00:00:00:00:00:00 and ff:ff:ff:ff:ff:ff from the list,
I've never seen a duplicate.  (all-zeros and all-ones are the result of
the eeprom dying in various ways, or a driver getting confused.  Both
will work until you get a second machine with the same problem)

-- 
Michael Richardson <mcr+IETF@sandelman.ca>, Sandelman Software Works

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