[libvirt-users] Using libvirt networking properly.

Hi, I'm interested in a setup in which one guest receives all its networking services (routed IPv4, dhcp, tftp, dns) from another, which is connected via a routing through the hypervisor. I think this is a lot like Guest C and Guest B in the diagram at http://libvirt.org/archnetwork.html. I have experimented with setting the network between Guest B and the hypervisor as a routed network, and the network between Guest B and Guest C as an isolated network. The problems I am having is that I am not sure how to set up a persistent static route to Guest C via Guest B, (I created a file with the route called route-virbr3 in /etc/sysconfig/network-scripts on the hypervisor, but it doesn't seem to do anything), and the changes I need to make to allow traffic with Guest C's source IP to come from Guest B's interface with the hypervisor seems to get overwritten or superceded by additional rules that are created when I start my machine.) I can see something about a qemu-ifup script mentioned at http://www.linux-kvm.org/page/Networking. Should I create something like that and put some sort of `ip route add` command in it? When should that script be called? Is there a way to specify the necessary firewall and routing rules in the xml network configuration? I am working with a Fedora 16 hypervisor and Guest B is a Centos 6 machine. I'd like to use all sorts of different distributions where Guest C is. Regards, Andrew.