nanog mailing list archives

Re: BCP for Private OUI / address assignments?


From: isabel dias <isabeldias1 () yahoo com>
Date: Tue, 25 Nov 2008 09:09:43 -0800 (PST)

Someone is basicly "twicking the mail headers" by sending messages like "nanog () 
85d5b20a518b8f6864949bd940457dc124746ddc nosense org"-who is?


OUI...yes, great topic! Now mind me asking but why would you need a "private" OUI if the well-known (registed) list is 
quite public and everyone has a reserved allocation? (vendors have)
and yes as far as i am aware all can be spoofed...up to the available anti-spoofing rules, plenty of google 
literature........just to check the theory points of failure  .....

Now the question is do mac adresses change w/ IPv6? Is there a relation w/ IPv4/6 format type and OUI format type ?

we might have heard of the IPv6 source address spoofing .....
http://www.cuba.ipv6-taskforce.org/pdf/isatap.pdf

...and w/ the translation to the OUI w/ v6 ......
http://tools.ietf.org/html/draft-eastlake-ethernet-iana-considerations-08










--- On Mon, 11/24/08, Mark Smith <nanog () 85d5b20a518b8f6864949bd940457dc124746ddc nosense org> wrote:

From: Mark Smith <nanog () 85d5b20a518b8f6864949bd940457dc124746ddc nosense org>
Subject: Re: BCP for Private OUI / address assignments?
To: peter () peter-dambier de
Cc: nanog () nanog org
Date: Monday, November 24, 2008, 10:01 PM
Hi,

On Mon, 24 Nov 2008 19:35:07 +0100
Peter Dambier <peter () peter-dambier de> wrote:

I also found this one helpful

http://www.iana.org/assignments/ethernet-numbers

===
The CFxxxx Series

RFC 2153 describes a method of usings a "pseudo
OUI" for certain
purposes when there is no appropriate regular OUI
assigned.  These are
listed here.

CF0001  Data Comm for Business                        
         [McCain]
===

I remember we had IBM Token-Ring equipment and they
suggested
to always use "CF..." and never rely on the
programmed MAC for SNA.


On an ethernet network, CF is a multicast destination
address, or, as a
source, I'm pretty sure it indicates that the frame
contains a source
route for use with translational bridging.

The locally assigned 0x02 bit would be better to use. Be
aware that
Microsoft have decided to "reserve" some locally
assigned addresses
in the range 02-BF, and 02-01 through 02-20 for use with
their load
balancing / high availability product, rather than use one
of their
proper OUIs. Apparently you're not supposed to be using
these
address ranges because the locally assigned address space
is so large,
before you use this Microsoft product, so if you are, too
bad. You'll
have to change your previous local assignments, or somehow
change
Microsoft's software. Within Wireshark it shows it as
used by
Microsoft, which implies official assignment to Microsoft.
The
Wireshark people won't change it, so that gives it a
level of
legitimacy. I think that's a slippery slope.

(It's a pet hate of mine that certain organisations
force their private
address space assignments (RFC1918 or IEEE locally
assigned) on
outsiders. It's supposed to be private so outsiders
don't see it or
don't have to work around it!)

Regards,
Mark.

-- 

        "Sheep are slow and tasty, and therefore must
remain constantly
         alert."
                                   - Bruce Schneier,
"Beyond Fear"


      


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