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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Exercise caution here. In cases where multiple switches reside
at layer2, including aggregators, configured to inject option-82 “AS A
RELAY” – they will ALL see the broadcast and you will receive
multiples. … Think of the seagulls in ‘Finding Nemo’ all
crying ‘mine, mine, mine, mine, mine, mine, mine, …’.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'> <o:p></o:p></span></p>
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color:#1F497D'><o:p> </o:p></span></p>
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<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
dhcp-users-bounces@lists.isc.org [mailto:dhcp-users-bounces@lists.isc.org] <b>On
Behalf Of </b>Marty Sørensen<br>
<b>Sent:</b> Wednesday, February 04, 2009 11:22 AM<br>
<b>To:</b> Glenn Satchell; Users of ISC DHCP<br>
<b>Subject:</b> Re: DHCPINFORM<o:p></o:p></span></p>
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<p class=MsoNormal style='margin-bottom:12.0pt'>Hey Glenn,<br>
<br>
What if you have some L2 device (where the client is connected), not the L3
relay, that does DHCP snooping and add's option-82 in the packege for
validating the DHCP request, this is then dropped by the switch because the
server strip's the option-82 :-(<br>
<br>
Martin<o:p></o:p></p>
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<p class=MsoNormal>On Wed, Feb 4, 2009 at 2:02 PM, Glenn Satchell <<a
href="mailto:Glenn.Satchell@uniq.com.au">Glenn.Satchell@uniq.com.au</a>>
wrote:<o:p></o:p></p>
<p class=MsoNormal><br>
>Date: Wed, 4 Feb 2009 13:44:36 +0100<br>
>Subject: Re: DHCPINFORM<br>
>From: Marty Sørensen <<a href="mailto:buzzwork@gmail.com">buzzwork@gmail.com</a>><br>
>To: Users of ISC DHCP <<a href="mailto:dhcp-users@lists.isc.org">dhcp-users@lists.isc.org</a>><br>
>X-BeenThere: <a href="mailto:dhcp-users@lists.isc.org">dhcp-users@lists.isc.org</a><o:p></o:p></p>
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<p class=MsoNormal>><br>
> Hey Randall,<br>
><br>
> Thanks for the reply. It seens that the switch relay's the option-82 OK,
in<br>
> this case, but the server drops it ?<br>
><br>
> Martin<br>
><o:p></o:p></p>
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<p class=MsoNormal>DHCPINFORM is unicast to the dhcp server, so the switch's
relay never<br>
sees it. Relays only see broadcast packets, then add the option-82 and<br>
forward tot he dhcp server.<br>
<br>
See the posts earlier today about how responses to DHCPINFORM don't<br>
look at existing lease data. This includes any options added by the<br>
relay when it processed the DHCPDISCOVER.<br>
<br>
regards,<br>
<span style='color:#888888'>-glenn</span><o:p></o:p></p>
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