Experimente este comando
sudo dhclient -v
Não deve haver nenhum erro. Meu resultado bem-sucedido se parece com isso,
Listening on LPF/eth3/00:e0:52:ce:a0:f6
Sending on LPF/eth3/00:e0:52:ce:a0:f6
Listening on LPF/eth2/00:50:43:00:f5:c7
Sending on LPF/eth2/00:50:43:00:f5:c7
Listening on LPF/eth0/20:cf:30:4f:60:43
Sending on LPF/eth0/20:cf:30:4f:60:43
Sending on Socket/fallback
DHCPDISCOVER on eth3 to 255.255.255.255 port 67 interval 3
DHCPREQUEST of 192.168.11.100 on eth2 to 255.255.255.255 port 67
DHCPREQUEST of 192.168.1.107 on eth0 to 255.255.255.255 port 67
DHCPACK of 192.168.1.107 from 192.168.1.1
RTNETLINK answers: File exists
bound to 192.168.1.107 -- renewal in 40407 seconds.