**** This works **************** cat nw1.xml <network> <name>nw1</name> <domain name='nw1' /> <forward mode='nat' dev='eth2'/> <ip address='192.168.101.1' netmask='255.255.255.0'> <dhcp> <range start='192.168.101.128' end='192.168.101.254'/> </dhcp> </ip> </network> [root@localhost nw]# virsh net-create nw1.xml Network nw1 created from nw1.xml [root@localhost nw]# virsh net-list --all Name State Autostart Persistent ---------------------------------------------------------- nw1 active no no default active yes yes ****** FAILS when given the same ip address range of an existing virtual interface ******* [root@localhost nw]# cat nw2.xml <network> <name>nw2</name> <domain name='nw2' /> <forward mode='nat' dev='eth2'/> <ip address='192.168.101.1' netmask='255.255.255.0'> <dhcp> <range start='192.168.101.128' end='192.168.101.254'/> </dhcp> </ip> </network> [root@localhost nw]# virsh net-create nw2.xml error: Failed to create network from nw2.xml error: internal error: Network is already in use by interface virbr1 ****** PASS - on giving diff ip range ******* [root@localhost nw]# cat nw3.xml <network> <name>nw3</name> <domain name='nw3' /> <forward mode='nat' dev='eth2'/> <ip address='192.168.102.1' netmask='255.255.255.0'> <dhcp> <range start='192.168.102.128' end='192.168.102.254'/> </dhcp> </ip> </network> [root@localhost nw]# virsh net-create nw3.xml Network nw3 created from nw3.xml [root@localhost nw]# virsh net-list --all Name State Autostart Persistent ---------------------------------------------------------- nw1 active no no nw3 active no no default active yes yes Any suggestions on what could be wrong here ? Thanks, G