configured dhcp server.

# cat /etc/dhcpd.conf
ddns-update-style interim;
ignore client-updates;

subnet netmask {

# --- default gateway
option routers;
option subnet-mask;

# option nis-domain "domain.org";
# option domain-name "domain.org";
# option domain-name-servers;

option time-offset -18000; # Eastern Standard Time
# option ntp-servers;
# option netbios-name-servers;
# --- Selects point-to-point node (default is hybrid). Don't change this unless
# -- you understand Netbios very well
# option netbios-node-type 2;

default-lease-time 21600;
max-lease-time 43200;

clinet is also fedora -2 . i used # netconfig to configure dhcp client options . when i use # ifconfig , i donot get a ip from the dhcp server. i get the same old static IP which was earlier configured. why is it so ? how can i get a ip from the dhcp server on the client ? in windows , .....ipconfig /flushdns or ipconfig /renew or is used.