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<div class="moz-cite-prefix">Normal? No, this goes against a lot of
things networking, so definitely not kosher. Two mac's in a
broadcast domain is an extremely bad thing usually causing a
switch to start flooding unicast traffic within a vlan. Microsoft
thought this was a great way to do redundancy with Network
Load-Balancing replicating macs among cluster members until
network people realized it was breaking their lans (essentially
turning switches into hubs). I have some mega-outages I can
attribute to this commonly over the years...<br>
<br>
Does it happen? Sure - as chinese companies clone each other and
other legit vendor hardware apparently eeprom data and all, not
bothering to register an oui id themselves, I'm not entirely
surprised. Buy those $5 ebay generic nics in bulk, i'm sure
you'll start getting mac collisions.<br>
<br>
Another reason to stay with reputable sources of hardware...<br>
<br>
I'd be curious what hardware it is being cloned indiscriminately,
as would whoever owned the rights to the registered OUI.<br>
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<a href="https://www.wireshark.org/tools/oui-lookup.html">https://www.wireshark.org/tools/oui-lookup.html</a><br>
<br>
-mb<br>
<br>
<br>
On 02/06/2014 04:50 PM, Daniel Stasinski wrote:<br>
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<blockquote
cite="mid:CAL_oeF1kbdvKeMF4tbF8RmZB_gPh6_YgDqwpGPBzcdotUY6NYQ@mail.gmail.com"
type="cite">
<pre wrap="">The past few days I've been trying to solve a mystery.
I've run a disability chat room for 17 years now and the whole time we
have had our own custom chat client that connects to a customized
ircd. For the identd portion of the connect, I have always used an 8
digit random number but as of v3 of the client, I seeded the random
number generator with their MAC address so their identd would be the
same if they re-installed. I have always been under the impression
that no two devices would ever share the same MAC. Note that this
isn't a security issue for the site, it's just a convenience thing for
me.
In the last couple of months, 4 people have come in with duplicate
id's. This has never happened before. Finally today a new guy came
in and he turned out to be a programmer too so we talked about it and
he gave me his pc's mac address. 58-2c-80-13-92-63. On a whim, I
googled it and holy crap!
I'm going to switch algorithms but I'm still curious, is it normal for
vendors to recycle MAC addresses?
Daniel
</pre>
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