To access official Ubuntu documentation, please visit:
http://help.ubuntu.com/vitaly@Emporio:~$ sudo dhclient
[sudo] password for vitaly:
Internet Systems Consortium DHCP Client V3.1.2
Copyright 2004-2008 Internet Systems Consortium.
All rights reserved.
For info, please visit
http://www.isc.org/sw/dhcp/Listening on LPF/eth0/00:14:2a:bb:82:50
Sending on LPF/eth0/00:14:2a:bb:82:50
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 7
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 21
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 15
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 8
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 4
No DHCPOFFERS received.
No working leases in persistent database - sleeping.
vitaly@Emporio:~$