location of option12

Jeffrey Hutzelman jhutz at cmu.edu
Wed Nov 12 04:52:28 UTC 2008

--On Wednesday, November 12, 2008 09:31:48 AM +0530 abhijit khadatare 
<anks030 at gmail.com> wrote:

> Thanks Jeffrey,
>     ur correct about encoding. Option 82 is placed before end option
> (rfc3046)

This is only REQUIRED in the case of a relay agent adding this option.  A 
DHCP server's reply might not have option 82 last, especially if the size 
of options is large enough to require the use of option-overload, since 
option 82 is not permitted to appear in the overloaded sname or file.

I wasn't present when these requirements were written, but presumably the 
intent was to simplify options processing in relay agents, especially those 
in layer-2 devices, and to allow for the fact that a relay agent doesn't 
get to participate in the negotiation by which a client indicates to the 
server that it supports option-overload, and thus the server cannot safely 
assume a relay agent will support option-overload, even when the client and 
server both do.

> , in similar way there
> is something about option12
> thanks once again for ur reply.

No special handling of this sort is specified for the hostname option.

-- Jeffrey T. Hutzelman (N3NHS) <jhutz+ at cmu.edu>
   Carnegie Mellon University - Pittsburgh, PA

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