I have worked on my Ubuntu Server host for weeks now and I just can not manage to get the virtual machines into the network.... here's what I need to do:
I need to be able to create virtual machines that have IP addresses that can be reached from the outside (192.168 network). I need to be able to connect to the virtual machines through ssh, ftp, http and preferably https, anything else doesn't matter that much.
So far everything seems simple enough and I have a lot of leeway in terms of IP address range and server/client configuration. I have the option of taking part of a /24 net as most IPs aren't used, and if it's absolutely necessary I have the option of creating a new /24 subnet. Also have the option of reformatting and reinstalling OS on the host and recreating the virtual machines as nothing has been done other than trying to get virtual machines to work.
I would prefer if the virtual machines were just part of the normal network which would be 192.168.5.0/24. The host machine has 2 network cards so I don't even necessarily need the Host to be connectable in the same /24 network.
I have tried (I think) just about everything from about 5 different tutorials on bridging (giving br0 the same IP that eth0 used to have (Host is able to connect to VM and vice versa, VM doesn't have outside network access), having eth0 set up like it always was and having br0 have a different IP (same as above), NAT with port forwarding (which I would have preferred not to use but will if it works), turning off one of the hosts network cards and just using one of them, different subnets.... etc. I do know my way around iptables fairly well....
Host is 64bit Ubuntu Server 12.04, using libvirt/kvm.
edits: Local network is 192.168.5.0/24, host has static ip 192.168.5.254, GW .5.1 which is also nameserver. We have a second Local network at 192.168.10.0/24 with .10.1 GW, but both hosts and VMs were supposed to go into the .5 subnet. The .10 subnet isn't required, but it wouldn't be horrible if the Host were only accessible in the .10 subnet.