Re: [dhcwg] Reg RFC6704 (Forcerenew Nonce Authentication)

["Bernie Volz (volz)" <[e-mail]>]

Just to extend Ted's comments a bit - one issue is how long does the
server keep the information for the Inform only clients. When the
reconfigure-key is associated with a lease, we have a lease time; there is
no such item for Inform. This could be tied to
draft-halwasia-dhc-inform-refresh-time-opt (obviously it should be kept
longer than the refresh time), but that work might also reduce the need
for this -- at least it bounds the period where information may be stale.

While in theory having Reconfigure for Inform isn't a bad concept, it just
strikes me as overkill - do we really have a problem? Especially for IPv4
which we hope deprecate.

I'm also not sure how many clients do just Informs Š yes, there are lots
of clients that do send Informs but they've usually also done Discover/...

It is interesting that RFC 3315 accommodates Information-Request; not sure
why RFC 6704 didn't - I would guess because RFC 3318 didn't.

- Bernie

On 9/11/12 9:45 PM, "Gaurav Halwasia (ghalwasi)" <[e-mail]>
wrote:

>Hi Ted,
>
>Thanks for your comments.
>
>I am talking about a deployment where we do create *session* database for
>hosts either based upon DHCP packet (Discover) or the normal IP packet in
>case few of the hosts has not done DHCP but instead has just DONE DHCP
>INFORM to get the config parameters. So in this kind of deployment we do
>anyways maintain the session(or binding in terms of DHCP) database on the
>box. Having said that I don't think storing client information is a
>problem (at least in this deployment). The only extra thing which we
>would need to store is a 'nonce'.
>So I think it will be really useful to have nonce in INFORM-ACK callflow
>as it will also help in the usability of Forcerenew as per 6704.
>
>Thanks,
>Gaurav 
>
>-----Original Message-----
>From: Ted Lemon [mailto:[e-mail]]
>Sent: Wednesday, September 12, 2012 2:09 AM
>To: <[e-mail]>
>Cc: Gaurav Halwasia (ghalwasi); [e-mail]
>Subject: Re: [dhcwg] Reg RFC6704 (Forcerenew Nonce Authentication)
>
>I didn't say that FORCERENEW for DHCPINFORM clients was hard.   I said it
>would impact performance.   We would go from DHCPINFORM being a
>lightweight read-only operation to a heavyweight read/write operation.
>I guess we could forgo the sync-before-ack logic of stateful DHCP, but
>this would add a lot of complexity to a performance-critical code section.
>
>So yeah, from an implementation point of view, I don't really like this
>idea.   It seems trivial until you think about the impact it has either
>on performance or on implementation complexity.   If there's strong
>demand for it with a clear use case, then I think that's fine.    I
>wasn't able to tease one out of your rather dense message-could you try
>to state your use case in a short paragraph or two?
>
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