[libvirt] question on network interface of LXC domain

Hello there with newest libvirt, when I connect to the container via console, then execute "ifconfig", there will be no output, though the network works fine. and "/proc/net/dev" of container seems good too. (has entries about "eth0" and "lo"). I traced the call procedure of "ifconfig", it reads the infomations of network interface from "/proc/net/dev" and vise visa. so I'm confused about what cause this problem. there is no problem with libvirt-0.8.0-4. Thanks and Regards Osier