Re: Duplicate MAC prefixes in nmap-mac-prefixes

["DePriest, Jason R." <jrdepriest () gmail com>]

I know this isn't unique to nmap.

What is the benefit of the IEEE assigning multiple vendors to the same
vendor prefix?

Did this issue slowly arise from companies being purchased by other
companies or going out of business?

It doesn't make sense that something that is supposed to be unique by
vendor isn't actually unique by vendor.

Again, I realize that this isn't something nmap can fix, I just want
to understand why we have this problem in the first place.

Thanks.

-Jason

On Wed, Nov 11, 2009 at 9:30 PM, David Fifield <> wrote:
> I found that there are some duplicate prefixes in nmap-map-prefixes.
>
> 0001C8 Thomas Conrad
> 0001C8 Conrad
>
> 080030 Network Research
> 080030 Cern
> 080030 Royal Melbourne Inst OF Tech
>
> Their presence is harmless. When looking up a vendor by prefix, the
> first one listed will win. When looking up a prefix by vendor string (as
> with the --spoof-mac option), usually the first one will win, but there
> is a slight chance that a later one will win, if the linear probing in
> the hash table that stores the information wraps around the end of the
> table.
>
> David Fifield
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