[libvirt] existing bridge and no iptable rules

[Markus <mw netst at>]

hi,

i try to setup libvirt with an existing network setup (bridge with NO
physical device, routes and iptables are already configured, dhcp named
..) . this bridge should be available for the libvirt domains.
now the problem: every configuration i tried ends in iptable rules
beeing created which mess with my network setup (e.g. i try to route vpn
traffic from a guest to another network outside)

is there a way of defining a virtual network / network source / bridge
for domains that takes an existing bridge and does no setup ( ip,
iptables, .. )?

thanks, markus