Subject: Re: Renew after a move to another subnet while powered up

From: Ralph Droms <[email-masked]>
Date: Thu, 06 Apr 2000 17:40:12 -0400

As an aside - in theory, the DHCP client on the laptop would be informed 
that the laptop has been disconnected and reconnected to a network segment 
(all the interface might know is that carrier was lost for some period of 
time).  The DHCP client would go into INIT-REBOOT state immediately and, 
through a broadcast REQUEST, the DHCP server can determine if the client is 
still on the same network segment.

In practice, I don't know that any DHCP clients do receive notice from the 
interface about loss of connectivity...

- Ralph

At 12:47 PM 4/6/00 -0400, you wrote:
>I would like to know whether a DHCP Server should send a NAK if a client
>moves from one subnet to another while still powered up and the renew is
>sent from the client to the server at the proper time (1/2 the lease time).
>
>Here is the scenario.
>
>I have two subnets and each have a range that is served by the same DHCP
>Server.  A laptop is plugged into one of the subnets and is started.  The
>lease that is given out to the client is for 1 hour.  Five minutes later the
>laptop is unplugged and plugged back in to a connection on the second
>subnet.  The user did not shut the machine down.  They just unplugged the
>network cable, moved to say an adjacent office, and plugged back in.
>However, the new connection is on another subnet from the first.  When
>another 25 minutes goes by the laptop does a renew.  At this point I would
>like to know what the DHCP server should do.  Should it send a NAK, should
>it stay silent or should it send an OFFER?  In your response could you
>please indicate where in RFC 2131 it gives the proper behaviour?
>
>Thanks,
>Dean Parkinson

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From: Ted Lemon <[email-masked]>
Date: Thu, 06 Apr 2000 16:28:40 -0700

> interface about loss of connectivity...

I think the latest OpenTransport client does.

			       _MelloN_