Hi All., I am not sure if this is possible in xen via Libvirt, but what I am trying to do is, I want libvirt to launch a VM and attach a pre-created tap interface to that VM ( I do not want XEN to create one, as I am running a lot of custom scripts on my tap interface). I also dont want xen to attach this tap interface to a bridge. For example, lets say I have created a tap interface with name "tap123456" when libvirt launches my VM in xen, I want the VM to read its networking info from this tap interface. But I wasn't so successful in doing this when ever I am trying to do this, I am seeing the following error message "VmError: Device 0 (vif) could not be connected. Hotplug scripts not working." and "error: POST operation failed: xend_post: error from xen daemon: (xend.err 'Device 0 (vif) could not be connected. Cannot rename interface vif4.0. An interface with name tap12345 already exists.')". But I dont want xen to create another interface and rename it, rather want xen to use the existing one === output of lsmod === bash-4.1# lsmod | grep xen xen_acpi_processor 4465 0 xen_netback 25455 0 [permanent] xen_gntdev 9504 2 xen_evtchn 4899 3 xenfs 2943 1 xen_privcmd 4972 19 xenfs ==== end of output ==== My Configuration : Centos 6.2 with Xen 4.2.5 along with Libvirt Libvirt Configuration file, <domain type='xen'> <name>raghu_12345</name> <uuid>12113325-d948-4a1b-b673-888a16b90726</uuid> <memory>1048576</memory> <vcpu>1</vcpu> <os> <type>hvm</type> <loader>/usr/lib/xen/boot/hvmloader</loader> <boot dev='hd'/> </os> <on_poweroff>destroy</on_poweroff> <on_reboot>restart</on_reboot> <on_crash>restart</on_crash> <features> <pae/> <acpi/> <apic/> </features> <devices> <emulator>/usr/lib/xen/bin/qemu-dm</emulator> <interface type="ethernet"> <mac address='00:25:90:3f:25:91'/> <!-- I want this mac to be mac address of a vm --> <target dev='tap123456'/> </interface> <disk type='file' device='disk'> <source file='~/tmp/lucid.img'/> <target dev='hda'/> </disk> <console type='pty'> <target port='0'/> </console> <graphics port='-1' type='vnc' autoport='yes' listen='0.0.0.0'/> </devices> </domain> I have a pre-created tap interface with name 'tap123456' with all the networking setup with dhcp and dns running. Thanks for your time and help. Regards Raghu