networking - eth0 on lxc does not work

I am facing some problems that the eth0 on lxc container does not work. I already tried
Bridging LXC containers to host eth0 so they can have a public IP, but it does not help.

On my host (Ubuntu on virtualbox):

# cat /proc/sys/net/ipv4/ip_forward
1

config

# cat /var/lib/lxc/config
lxc.config
lxc.utsname=ubuntu
lxc.network.type=veth
lxc.network.link=br0
lxc.network.flags=up

I created a container with the above config

# lxc-create -t centos -f config -n centos1

then launch

# lxc-start -d -n centos1
# lxc-console -n centos1

It seems veth is properly connected because the host machine says

# brctl show
bridge name    bridge id           STP enabled    interfaces
br0            8000.080027bb0aca   no             eth0
                                                  veth48BKPz
lxcbr0         8000.000000000000   no

And the default gateway seems also be set correctly on the host

# route -n
Kernel IP routing table
Destination    Gateway        Genmask          Flags    Metric  Ref   Use  Iface
0.0.0.0        192.168.11.1   0.0.0.0          UG       100     0       0  br0
10.0.3.0       0.0.0.0        255.255.255.0    U        0       0       0  lxcbr0
192.168.11.0   0.0.0.0        255.255.255.0    U        0       0       0  br0

On the lxc container

# route -n
Kernel IP routing table
Destination    Gateway        Genmask          Flags    Metric  Ref   Use  Iface
0.0.0.0        192.168.11.1   0.0.0.0          UG       0       0       0  eth0
169.254.0.0    0.0.0.0        255.255.0.0      U        1009    0       0  eth0
192.168.11.0   0.0.0.0        255.255.255.0    U        0       0       0  eth0

Any help?