Re: [Qemu-discuss] macvlan/macvtap: guest/host cannot communicate when network cable is unplugged

[ching]

On 08/24/2012 12:22 PM, ching wrote:
> Hi all,
>
> I try to setup guest network with macvlan, as guest cannot communicate with 
> host directly, i try to workaround by configuring host to using a macvlan 
> interface
>
> host: Gentoo x64, kernel 3.5.2, qemu-kvm 1.1.1-r1, libvirt 0.9.13
> guest: Ubuntu 12.04, kernel 3.4.9, virtio-net
>
> The host is using macvlan (interface name: znet0, bridge mode)
>
> The guest is using macvtap managed by libvirt (interface name: macvtap0, 
> bridge mode)
>
>
> I am facing a strange problem that the guest/host can communicate only when 
> the network cable of the ethernet adapter is connected.
>
> Do anyone have similar problem? Am i missing something?
>
>
>
> The network config of the host
>
> $ifconfig
>
> macvtap0  Link encap:Ethernet  HWaddr 52:54:xx:xx:xx:xx
>           inet6 addr: fe80::xx:xx:xx:xx/64 Scope:Link
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:70 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:84 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:500
>           RX bytes:9036 (8.8 KiB)  TX bytes:14734 (14.3 KiB)
>
> znet0     Link encap:Ethernet  HWaddr 00:60:xx:xx:xx:xx
>           inet addr:192.168.1.2  Bcast:192.168.1.255  Mask:255.255.255.0
>           inet6 addr: 2002:xx:xx:xx:xx/64 Scope:Global
>           inet6 addr: fe80:xx:xx:xx:xx/64 Scope:Link
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:4463190 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:12527522 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:0
>           RX bytes:3959213697 (3.6 GiB)  TX bytes:18590336476 (17.3 GiB)
>
> $ip -d link show
>
> 10: address@hidden: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue 
> state UP mode DEFAULT
>     link/ether 00:60:xx:xx:xx:xx brd ff:ff:ff:ff:ff:ff
>     macvlan  mode bridge
> 17: address@hidden: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc 
> pfifo_fast state UNKNOWN mode DEFAULT qlen 500
>     link/ether 52:54:xx:xx:xx:xx brd ff:ff:ff:ff:ff:ff
>     macvtap  mode bridge
>
> Regards,
> ching

have anyone tried the communication between host/guest using macvlan interface 
successfully?

I already set the macvlan to "bridge" mode, and unplug my network cable to 
ensure no external switch is involved.