When cloning a VM you may find that the network cannot get a DHCP address. This probably means eth0 is now eth1. This happens because the Ethernet address of the network adapter has changed. Udev handles assigning this device name, since eth0 is already assigned, it just assigns another device name (eth1). To fix this, remove the offending entries from:

/etc/udev/rules.d/70-perisistent-net.rules

Then reboot.