Reinicie a interface de rede do Ubuntu depois de editar a interface em:
/etc/networks
e
/etc/network/interfaces
Desligue a interface utilizando o comando: ifdown -a
Ative a interface utilizando o comando: ifup -a
Pronto.
O que deverá aparecer, será algo semelhante a isso:
root@static-68-235-x-x:~# more /etc/networks
default 0.0.0.0
loopback 127.0.0.0
link-local 169.254.0.0
localnet 68.235.x.x
root@static-68-235-x-x:~# more /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
auto eth2
iface eth2 inet static
address 68.235.x.x
netmask 255.255.255.248
network 68.235.x.x
broadcast 68.235.x.x
gateway 68.235.x.x
# dns-* options are implemented by the resolvconf package, if installed
dns-nameservers 8.8.8.8
dns-search cust.tzulo.com
root@static-68-235-x-x:~#
