I don't know about rebuilding the file.

If DHCP server and DHCP client are fully compliant with RFC2131 the DHCP
client will send a DHCPDECLINE message to the DHCP server indicating the
address is in use.

4.3.3 DHCPDECLINE message
If the server receives a DHCPDECLINE message, the client has discovered
through some other means that the suggested network address is already
in use.  The server MUST mark the network address as not available and
SHOULD notify the local system administrator of a possible configuration
problem.

All this is in RFC2131 http://www.ietf.org/rfc/rfc2131.txt?number=2131.
It also depends on how the client and server are configured. It also
contains information on clients renewing their lease and requesting the
same IP address. I think the default is allow them to keep their address
but again, it depends on how the DHCP server is configured.

Enjoy,
Paul
-----Original Message-----
From: owner-kclug@marauder.illiana.net
[mailto:owner-kclug@marauder.illiana.net] On Behalf Of Lucas Peet
Sent: Saturday, September 27, 2003 10:29 PM
To: kclug@kclug.org
Subject: DHCP and Static Addresses

Ok.  Say I'm on a network that serves out IP's via DHCP.  Say I set my
IP address statically, using an IP address in the DHCP server's address
pool.  What happens when the DHCP server tries to hand out the IP
address from it's pool that I set statically?  There would then be 2
machines on the network with the same IP address. Which machine would
get booted offline?  Would they both?  How would the static one know
when it was okay to come back online again?

Also, is there a way to rebuild /etc/dhcpc/dhcpcd-ethX.cache using the
.info file manually (say to re-request a specific IP address which the
lease has expired)?  Is there any other way to force a request of a
specific IP address from the DHCP server, and have it give it to you, if
it's still available?

Thanks for all your input.

-Lucas