Re: DAD question

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> > So from this sample a total of 10 MAC addresses occur more than once
> > (different customers, different locations).
> 
> Interesting.  Are these different machines/interfaces with the same Mac addresses, or the same machine connecting via some other path or location.

I have duplicates on different BRAS boxes in widely different
geographical locations, plus these are almost exclusively residential
users. That makes it highly unlikely that they are the same machine
connecting  via some other path/location.

> My question was about machines/interfaces.  That is, are we seeing manufacturing mistakes, etc.?

Explicit manufacturing mistakes (e.g. vendor turning our X copies of
the same box with the same MAC address) have been reported on ops
lists several times in the past.

Software errors resulting in duplicates have been reported multiple
times (see for instance my reply to Michael Richardson on this list).

The possibility of explicitly configuring the MAC address exists in
many operating systems (e.g. the FreeBSD box I'm typing this on).

The easy availability of "MAC address cloning" was mentioned by Mikael
Abrahamsson. Note that "MAC address cloning" is used in home routers,
not just in VM environments.

Steinar Haug, Nethelp consulting, [e-mail]