sudo su
brctl addbr br0
ip addr add 192.168.3.100/24 dev br0
ip link set br0 up
[ -d /etc/qemu ] || mkdir /etc/qemu
touch /etc/qemu/bridge.conf
echo "allow br0" >> /etc/qemu/bridge.conf
QEMU:
qemu-system-i386 \
-m 256 \
-smp 2 \
-enable-kvm \
-net nic,model=rtl8139 -net bridge,br=br0