[fedora-virt] Isolated Virtual Network

I have a Fedora 18 server hosting several Fedora 18 guests with a bridge. The server, guests of the server, and peers of the server can all freely interact. I have YUM repositories available via http and home and shared directories available via nfs from the server. And DNS, authentication and policies for autofs and sudo are available from IPA on one of server guests. Life is good. [root@host ~]# cat /etc/sysconfig/network-scripts/ifcfg-em1 # Configured manually BRIDGE=br1 DEVICE=em1 HWADDR=00:1C:C4:AE:57:4F ONBOOT=yes TYPE=Ethernet [root@host ~]# cat /etc/sysconfig/network-scripts/ifcfg-br1 # Configured manually BOOTPROTO=static DEFROUTE=yes DELAY=0 DEVICE=br1 DNS1=192.168.1.11 DNS2=75.75.76.76 DNS3=75.75.75.75 DOMAIN=hunter.org GATEWAY=192.168.1.254 IPADDR=192.168.1.10 IPV4_FAILURE_FATAL=no IPV6INIT=no NAME="System br1" ONBOOT=yes PREFIX=24 STP=on TYPE=Bridge [root@host ~]# virsh net-dumpxml Subnet1 <network connections='4'> <name>Subnet1</name> <uuid>3a50ed6a-0350-e46e-5a9d-a6b159ce5c37</uuid> <forward mode='bridge'/> <bridge name='br1' /> <mac address='52:54:00:18:8F:47'/> </network> [root@host ~]# Now Fedora 19 comes along and I need to test new versions of the server guests in isolation from existing server guests and server peers; ie. everything except for the http and nfs services of the server. I welcome your suggestions.