Hi, I'm trying to get NAT networking running as described in http://libvirt.org/formatnetwork.html#examplesNAT But in the guest, ifconfig shows only the lo interface. I created the kvm image (debian lenny 5.0.3) directly with qemu-img and kvm, because virt- install also didn't work. Afterwards I created the XML file for libvirt: <domain type='kvm'> <name>hadoop1</name> <uuid>c40b6644-362a-e5ab-8825-cd1a7fbe24eb</uuid> <memory>524288</memory> <currentMemory>524288</currentMemory> <vcpu>1</vcpu> <os> <type arch='x86_64' machine='pc'>hvm</type> <boot dev='hd'/> </os> <features> <acpi/> <apic/> <pae/> </features> <clock offset='utc'/> <on_poweroff>destroy</on_poweroff> <on_reboot>restart</on_reboot> <on_crash>restart</on_crash> <devices> <emulator>/usr/bin/kvm</emulator> <disk type='file' device='disk'> <driver name='qemu' type='qcow2'/> <source file='/var/lib/libvirt/images/hadoop1.qcow2'/> <target dev='hda' bus='ide'/> </disk> <interface type='network'> <mac address='52:54:00:05:74:bb'/> <source network='default'/> <model type='virtio'/> </interface> <!--serial type='pty'> <target port='0'/> </serial> <console type='pty'> <target port='0'/> </console--> <input type='mouse' bus='ps2'/> <graphics type='vnc' port='-1' autoport='yes' keymap='de-ch'/> <video> <model type='cirrus' vram='9216' heads='1'/> </video> </devices> </domain> The network config is: <network> <name>default</name> <bridge name="virbr0" /> <forward/> <ip address="192.168.122.1" netmask="255.255.255.0"> <dhcp> <range start="192.168.122.2" end="192.168.122.254" /> </dhcp> </ip> </network> ifconfig of the host (needs cleanup, I know): eth1 Link encap:Ethernet Hardware Adresse 00:1c:25:18:4d:e6 UP BROADCAST RUNNING MULTICAST MTU:1500 Metrik:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 Kollisionen:0 Sendewarteschlangenlänge:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Speicher:fe200000-fe220000 eth1:avahi Link encap:Ethernet Hardware Adresse 00:1c:25:18:4d:e6 inet Adresse:169.254.6.97 Bcast:169.254.255.255 Maske:255.255.0.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metrik:1 Speicher:fe200000-fe220000 lo Link encap:Lokale Schleife inet Adresse:127.0.0.1 Maske:255.0.0.0 inet6-Adresse: ::1/128 Gültigkeitsbereich:Maschine UP LOOPBACK RUNNING MTU:16436 Metrik:1 RX packets:160751 errors:0 dropped:0 overruns:0 frame:0 TX packets:160751 errors:0 dropped:0 overruns:0 carrier:0 Kollisionen:0 Sendewarteschlangenlänge:0 RX bytes:27262569 (25.9 MiB) TX bytes:27262569 (25.9 MiB) virbr0 Link encap:Ethernet Hardware Adresse 4a:30:15:4d:b5:0d inet Adresse:192.168.122.1 Bcast:192.168.122.255 Maske:255.255.255.0 inet6-Adresse: fe80::8804:ecff:febc:fa54/64 Gültigkeitsbereich:Verbindung UP BROADCAST RUNNING MULTICAST MTU:1500 Metrik:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:299 errors:0 dropped:0 overruns:0 carrier:0 Kollisionen:0 Sendewarteschlangenlänge:0 RX bytes:0 (0.0 B) TX bytes:47842 (46.7 KiB) vnet0 Link encap:Ethernet Hardware Adresse 4a:30:15:4d:b5:0d inet6-Adresse: fe80::4830:15ff:fe4d:b50d/64 Gültigkeitsbereich:Verbindung UP BROADCAST RUNNING MULTICAST MTU:1500 Metrik:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:128 errors:0 dropped:0 overruns:0 carrier:0 Kollisionen:0 Sendewarteschlangenlänge:500 RX bytes:0 (0.0 B) TX bytes:16426 (16.0 KiB) wlan0 Link encap:Ethernet Hardware Adresse 00:1d:e0:08:89:21 inet Adresse:192.168.178.23 Bcast:192.168.178.255 Maske:255.255.255.0 inet6-Adresse: fe80::21d:e0ff:fe08:8921/64 Gültigkeitsbereich:Verbindung UP BROADCAST RUNNING MULTICAST MTU:1500 Metrik:1 RX packets:10608 errors:0 dropped:0 overruns:0 frame:0 TX packets:10358 errors:0 dropped:0 overruns:0 carrier:0 Kollisionen:0 Sendewarteschlangenlänge:1000 RX bytes:7515487 (7.1 MiB) TX bytes:1367200 (1.3 MiB) wmaster0 Link encap:UNSPEC Hardware Adresse 00-1D- E0-08-89-21-00-00-00-00-00-00-00-00-00-00 UP BROADCAST RUNNING MULTICAST MTU:1500 Metrik:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 Kollisionen:0 Sendewarteschlangenlänge:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Thanks for any help, Thomas Koch, http://www.koch.ro