The last parameter while creating a new host is used to configure a particular network driver that will be used when launching every new VM.
The available network drivers are as follows:
dummy: This is the default driver that does not enforce any particular network policy. Every VM connected on the same physical bridge will be able to freely talk to the others.
fw: This automatically creates iptable rules on the host executing the VM. This driver can be used to filter different TCP/UDP ports and ICMP for every VM.
ebtables: This automatically creates ebtable rules on the host to enable network isolation between different VMs running on the same bridge, but only on different /24 networks.
802.1Q: This is used to enable network isolation provided through host-managed VLANs with the 802.1Q standard. A bridge will be automatically created for each OpenNebula virtual network, and a VLAN tag will be attached to all the bridge traffic. Indeed, 802.1Q-compliant network switches must...