The Debian package of Xen don't change the network setup in any way. This
differs from the upstream version, which overwrites the main network card
(eth0) with a bridge setup and may break the network at this point..
To setup a bridge please follow the instructions in the manpage for
You can also change the /etc/xen/xend-config.sxp file and re-enable the Xen
included network setup by adding
to the file. But please note that this may or may not work.
So, to /etc/networks/interfaces then:
iface br0 inet static
bridge_ports regex vif.*
# if bridging eth0 as well:
# bridge_ports regex vif.* noregex eth0
# all eth and vif?
# bridge_ports regex (eth|vif).*
# if you want no IP address on the bridge,
# delete address, netmask, network, and broadcast line
# and change "iface br0 inet static" to "iface br0 inet manual"
In /etc/xen/xend-config.sxp, leave all (network-script ...) lines commented, and just uncomment the (vif-script vif-bridge) line.