I hope this is what you need
Terry
auto lo
iface lo inet loopback
terry@terry-desktop:~$ sudo dhclient eth0
[sudo] password for terry:
Internet Systems Consortium DHCP Client V3.1.1
Copyright 2004-2008 Internet Systems Consortium.
All rights reserved.
For info, please visit
http://www.isc.org/sw/dhcp/
Listening on LPF/eth0/00:16:e6:66:b1:ea
Sending on LPF/eth0/00:16:e6:66:b1:ea
Sending on Socket/fallback
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 6
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 10
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 16
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 9
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 16
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 4
No DHCPOFFERS received.
No working leases in persistent database - sleeping.
terry@terry-desktop:~$