In that case, there's a -r option to dhclient which according to the manpages is supposed to do a DHCP release.
I'm not sure what's wrong, but this doesn't actually do anything on my FC3 box. Tcpdump shows no DHCP_RELEASE packet is ever sent, and the original client doesn't exit either. But perhaps you might have better luck with it :)
Have you tried to kill original client first, than do -r thingie, and than restart the client (for example, ifdown ethx; ifup ethx)?
-- Aleksandar Milivojevic <amilivojevic@xxxxxx> Pollard Banknote Limited Systems Administrator 1499 Buffalo Place Tel: (204) 474-2323 ext 276 Winnipeg, MB R3T 1L7
