Subject: IP reconfiguration

From: Patrik Carlsson <[email-masked]>
Date: Wed, 03 Jan 2001 09:51:11 +0100

Hi!

I have a few questions how DHCP can handle reconfiguration of a client's
IP address. Consider the following scenario. There are a few clients
connected to a router A (which act as a bootp relay agent) which in it's
turn is connected to antoher router etc. Because of OSPF summarisation,
it will be necessary to change the subnet where the clients are located.
The clients can not be managed from a remote location and the only way
to change the IP address of the clients is to use DHCP. Is this
possible?

Case 1; What happens if the subnet of the router A is changed but the
clients still belong to the old subnet with the old IP addresses? When
its time for renewal, the packet sent to the DHCP server is a unicast
and will therefore not reach the server (since the clients information
about def. router are invalid). How does the client handle this? Does it
start to send broadcast?

Case 2; the router A keeps the old subnet but the clients negotiates
about new IP addressess. Is it possible to configure a client with a
completely new IP address (out of the existing subnet range)? In that
case, will information such as IP address, subnet mask, def router take
hange in exactly the same moment?

Can this be done in a different way?
Thanks!

/Patrik