[124759] in North American Network Operators' Group
Re: what about 48 bits?
daemon@ATHENA.MIT.EDU (John Peach)
Sun Apr 4 17:56:41 2010
Date: Sun, 04 Apr 2010 17:56:07 -0400
From: John Peach <john-nanog@johnpeach.com>
In-reply-to: <4BB90936.7090607@jsbc.cc>
To: nanog@nanog.org
Reply-To: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Sun, 04 Apr 2010 14:48:38 -0700
Jim Burwell <jimb@jsbc.cc> wrote:
> On 4/4/2010 08:46, Jonathan Lassoff wrote:
> > Excerpts from John Peach's message of Sun Apr 04 08:17:28 -0700 2010:
> >
> >> On Sun, 4 Apr 2010 11:10:56 -0400
> >> David Andersen <dga@cs.cmu.edu> wrote:
> >>
> >>
> >>> There are some classical cases of assigning the same MAC address to every machine in a batch, resetting the counter used to number them, etc.; unless shown otherwise, these are likely to be errors, not accidental collisions.
> >>>
> >>> -Dave
> >>>
> >>> On Apr 4, 2010, at 10:57 AM, jim deleskie wrote:
> >>>
> >>>
> >>>> I've seen duplicate addresses in the wild in the past, I assume there
> >>>> is some amount of reuse, even though they are suppose to be unique.
> >>>>
> >>>> -jim
> >>>>
> >>>> On Sun, Apr 4, 2010 at 11:53 AM, A.B. Jr. <skandor@gmail.com> wrote:
> >>>>
> >>>>> Hi,
> >>>>>
> >>>>> Lots of traffic recently about 64 bits being too short or too long.
> >>>>>
> >>>>> What about mac addresses? Aren't they close to exhaustion? Should be. Or it
> >>>>> is assumed that mac addresses are being widely reused throughout the world?
> >>>>> All those low cost switches and wifi adapters DO use unique mac addresses?
> >>>>>
> >>>>>
> >> Sun, for one, used to assign the same MAC address to every NIC in the
> >> same box.
> >>
> > I could see how that *could* work as long as each interface connected to
> > a different LAN.
> >
> That was a logic Sun used. Every NIC would be connected to a different
> subnet, so duplicate MACs shouldn't be a problem. For the most part
> this worked, but some situations required a unique MAC per NIC, and Sun
> had a bit you could flip to turn this on. I believe it was an OpenBoot
> prom variable called "local-mac-address?" which you'd set to true if you
> wanted it to use each NICs MAC instead of the "system MAC".
You can set the MAC address to whatever you want in Solaris, using
ifconfig and local-mac-address was (is) the PROM variable.
--
John
