With full bridging, we can connect the KVM guests directly to the host network, without using NAT. However, this setup requires an IP address, which is part of the host subnet, for each virtual machine. If you cannot allocate that many IP addresses, consider using the NAT network setup, as described in the Configuring NAT forwarding network recipe given before. In this networking mode, the virtual machines still use the host OS bridge for connectivity; however, the bridge enslaves the physical interface that is going to be used for the guests.
For this recipe, we are going to need the following:
- A server with at least two physical interfaces
- The ability to provision and start KVM instances with libvirt
- A running KVM instance