Subject: Re: DHCPNAK in response to DHCPRENEW

From: Stuart Cheshire <[email-masked]>
Date: Mon, 12 Jun 2000 13:27:48 -0700

>Stuart - RFC2131 is not clear on the required behavior
>of a DHCP client when it receives a DHCPNAK in response
>to a DHCPRENEW or DHCPREBIND message.  In practice, how
>do the various MacOS clients react in this situation?
>
>Thanks for the information about the AirPort.  Seems like
>just the right thing for my home network...
>
>- Ralph

In REQUESTING, RENEWING, REBINDING or INITREBOOT, a NAK puts the client 
back into INIT state and it sends a DISCOVER to get a new address.

In INIT state, if the client gets no OFFERs, but it *does* get a NAK, and 
the NAK contains an ASCII text message option (option 56), then the 
message is displayed to the user. This is a slight extension to the spec, 
in that RFC 2131 does not specify a behaviour for a NAK received in 
response to a DISCOVER, but if you do decide to send one to a Mac, and 
you put a message in it, then the Mac will display it. This can be 
useful, for example, when you are aware of a problem and are already 
working on it, to avoid a flood of calls to the support desk, by 
configuring a message that says, "We are out of addresses on this subnet. 
We are aware of the problem and will have it fixed by 10:00am."

If you want to test this, you'll need the latest Open Transport release, 
which is OT 2.6.2. I think it should be available for download on the web 
-- if not ask me and I can send you a copy.

Stuart Cheshire <[email-masked]>
 * Wizard Without Portfolio, Apple Computer