Dear list, Being a libvirt noob, I have some trouble understanding. It is about getting two different guest in the same network. *********** I've defined a network with libvirt. This is the source xml: <network> <name>private2</name> <uuid>9684f2c6-6fd0-491b-9cb5-80ee268b01ce</uuid> <bridge name='br2' stp='on' delay='0'/> <mac address='52:54:00:b0:0a:c5'/> <ip address='10.0.0.1' netmask='255.255.255.0'> <dhcp> <range start='10.0.0.20' end='10.0.0.254'/> </dhcp> </ip> <ip family='ipv6' address='2001:db8:ca2:3::1' prefix='64'> </ip> </network> There is no 'forward' identifier so this should define an isolated network. br2 Was not pre-defined, it appeard after defining this network with libvirt. *********** ps aux shows: /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/private2.conf *********** ip a shows: 11: br2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000 link/ether 52:54:00:b0:0a:c5 brd ff:ff:ff:ff:ff:ff inet 10.0.0.1/24 brd 10.0.0.255 scope global br2 valid_lft forever preferred_lft forever inet6 2001:db8:ca2:3::1/64 scope global valid_lft forever preferred_lft forever inet6 fe80::5054:ff:feb0:ac5/64 scope link valid_lft forever preferred_lft forever 12: br2-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel master br2 state DOWN group default qlen 1000 link/ether 52:54:00:b0:0a:c5 brd ff:ff:ff:ff:ff:ff *********** virsh net-list --all shows: Name State Autostart Persistent ---------------------------------------------------------- private2 active yes yes *********** Then I start two guests with different MAC-addresses and differt UUID's Both guests are set on DHCP. They share the same network config: <interface type='network'> <mac address='52:54:00:xx:xx:xx'/> <source network='private2'/> <model type='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> Both guests take a lot of time to boot, waiting for network configuration. Then they end up having the same IP address, not able to communicate with each other. What am I missing? Your advise is much appreciated.