Sometimes, it can not connect to internet from a virtual machine.
check the internet interface by
ifconfig -a
it should shows something like eth0 or eth1, this is the interface name
go to /etc/network/interfaces
to set dhcp simply put in
iface eth0 inet dhcp
if it is eth1, then iface eth1 inet dhcp
to set static ip, put in
iface eth0 inet static
address 192.168.0.2
netmask 255.255.255.0
gateway 192.168.0.1
dns-nameservers 166.111.8.28 166.111.8.29