DHCP option 82 behavior

David W. Hankins David_Hankins at isc.org
Mon Sep 11 21:44:03 UTC 2006

On Fri, Sep 08, 2006 at 05:00:28PM -0400, Curt Rask wrote:
> In this case, I know that the DHCP snooper will remove the option 82 
> information that was added prior to sending it back to the client.  Not 
> that that necessarily helps matters, much.

I suppose the first thing to admit is that there is no way for the
server to know with certainty, when the relay does not set giaddr,
if it is talking to a client or a relay.  So it would be best to err
on the side of speaking to a relay (since most clients will ignore
this option if it appears, we hope).  But, to also hold fast to the
576 (or mms option) limitation, since if it is transmitting directly
to a client, this may affect the client's ability to receive it.

This also means, however, that the server will still need to learn
the difference between cached and recently-provided relay agent

I've opened a ticket in your name in our tracking system.  Expect
to get email on this when its number comes up.

David W. Hankins	"If you don't do it right the first time,
Software Engineer		you'll just have to do it again."
Internet Systems Consortium, Inc.	-- Jack T. Hankins

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