Forcing expiration of DHCP lease

[Michael ODonnell]

OK, this seems like it should be obvious but I'm
not getting anywhere.

I work in a corporate environment where the
networking infrastructure (particularly the DHCP)
is all Windows stuff and the guy in charge of it
understands very little about DHCP and nothing at
all about Linux, so he's not much use.  I swapped
the NICs in my Linux box (let's say it previously
had the hostname linux) and the DHCP server has
now assigned my machine the name linux-1 since
it believes a lease with the old name is still
held by another interface (the old NIC).

I want to communicate to the server that it's
OK to assign the old name to my new interface
(I've put 'send host-name "linux";' into my
/etc/dhclient.conf) but until it's convinced
that the old lease should be abandoned it seems
unwilling to do it.  Meanwhile, other systems
that refer to my Linux box by name are failing
to find it.

In the past I've managed Linux dhcpd systems
where, as a last resort, I could hand-hack
the leases file and restart the DHCP server,
but that's not an option in this case.  I did
RTFM but can't find anything that tells how to
direct the client to inform the server that the
lease should expire.