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To: Akihiro Tominaga <tomy@gunpowder.Stanford.EDU>
cc: hackers@freebsd.org
Subject: Re: (wide) DHCP negotiation using the REQUEST_IPADDR option 
In-reply-to: Your message of "Fri, 17 Jan 1997 23:10:05 PST."
             <199701182013.MAA27661@gunpowder.Stanford.EDU> 
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Date: Sat, 18 Jan 1997 22:32:40 +0000
From: Brian Somers <brian@awfulhak.demon.co.uk>
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[.....]
> No.  Please consider about the following case.
> 
> A client is assigned 10.0.0.1 from server 'A'.
> The server 'A' goes down with some trouble.
> The client can't extend lease for 10.0.0.1 then gives up to use it.
> The client is assigned 10.0.0.2 from server 'B'.
> The lease for 10.0.0.1 expires.
> The server 'A' comes up again.  It has expired lease of 10.0.0.1
> The client can't extend the lease for 10.0.0.2, because of some trouble.
> 
> Now, the client goes to init-reboot state, and send DHCPREQUEST with
> requested-IP address "10.0.0.2".
> 
> Although server 'B' sends back ACK, but server 'A' sends back NAK
> previously, the client cannot use "10.0.0.2".
> 
> Do you understand?
[.....]

Yep - I conceed.  It must then be the case that when the lease expires,
the client will ask for the same IP again, but if it doesn't receive an
ACK, must *not* use that IP anyway (but should then send a request without
a suggested IP).

Assuming the above is correct, once an IP is given for a certain amount of
time, it *can't* be changed before that time expires without intervention
on both sides.  I was (incorrectly) expecting to be able to "change my
mind" from the server end.

I'll roll the FreeBSD patch back out - sorry if I've caused any grief.

Thanks.

-- 
Brian <brian@awfulhak.demon.co.uk>, <brian@freebsd.org>
      <http://www.awfulhak.demon.co.uk/>
Don't _EVER_ lose your sense of humour....