With CentOS 6 everthing is handled by udev now. Go into /etc/udev/rules.d and delete the 70-persistent-net.rules file and reboot. If you open it berfore hand you will most likey see the original NIC MAC listed as eth0 and the new one as eth1.
Now you need to edit /etc/sysconfig/network-scripts/ifcfg-eth0 and manually update to the MAC of your new NIC card.
Deleting the file forces the detection process to run again at boot with no baggage left over from the cloning process, namely the old NIC MAC address(es).
Si Ubuntu no detecta la red dentro de HyperV, hay que hacer esto:
sudo vi /etc/initramfs-tools/modules
& add below lines
hv_vmbus
hv_storvsc
hv_blkvsc
hv_netvsc
y luego..
update-initramfs –u
sudo reboot