[vbox-dev] Odd networking issue with VirtuaBox

[Klaus Espenlaub]

Maarten,

On 17.06.2015 10:22, Maarten Hoes wrote:
> Hi,
>
>
> Thanks.
>
> 'ping -6 www.google.com <http://www.google.com>' from a command prompt
> on the Windows host os works as expected, but 'ping6 www.google.com
> <http://www.google.com>' from within the CentOS guest vm gets no response.
>
> Here is the routing tables (output of 'ip -4/-6 route) of the CentOS guest:
>
> # ip -4 route
> default via 192.168.178.1 dev enp0s3
> 169.254.0.0/16 <http://169.254.0.0/16> dev enp0s3  scope link  metric 1002
> 192.168.178.0/24 <http://192.168.178.0/24> dev enp0s3  proto kernel
> scope link  src 192.168.178.33
>
> # ip -6 route
> unreachable ::/96 dev lo  metric 1024  error -101
> unreachable ::ffff:0.0.0.0/96 <http://0.0.0.0/96> dev lo  metric 1024
> error -101
> 2001:980:ed37:1::/64 dev enp0s3  proto kernel  metric 256  expires 6200sec
> unreachable 2002:a00::/24 dev lo  metric 1024  error -101
> unreachable 2002:7f00::/24 dev lo  metric 1024  error -101
> unreachable 2002:a9fe::/32 dev lo  metric 1024  error -101
> unreachable 2002:ac10::/28 dev lo  metric 1024  error -101
> unreachable 2002:c0a8::/32 dev lo  metric 1024  error -101
> unreachable 2002:e000::/19 dev lo  metric 1024  error -101
> unreachable 3ffe:ffff::/32 dev lo  metric 1024  error -101
> fe80::/64 dev enp0s3  proto kernel  metric 256
> default via fe80::2665:11ff:feed:e8d1 dev enp0s3  proto ra  metric 1024
> expires 1371sec

Rather mysterious. The packet trace shows that the guest gets the router 
advertisement correctly, and it gets used correctly as the destination 
MAC address for the attempts to open a connection. Just there's no answer.

I suspect the very same thing happens for ping6 (the capture only 
contains regular ping, v4).

Do you have a firewall somewhere (host, router) which drops "unknown" 
IPv6 traffic? It can't be a "nothing gets through" case, otherwise the 
router wouldn't respond with the mentioned router advertisement 
immediately after the router solicitation request.

There are no incoming "Neighbor solicit" messages, but the router could 
of course still remember the details from the earlier communication 
initiated by the VM.

It also can't be a complete failure to receive multicast traffic, as the 
trace shows some incoming IPv4 and IPv6 multicasts.

Klaus

>
>
>
>
> - Maarten
>
>
>
> On Wed, Jun 17, 2015 at 9:59 AM, Aleksey Ilyushin
> <aleksey.ilyushin at oracle.com <mailto:aleksey.ilyushin at oracle.com>> wrote:
>
>     Hi,
>
>     First you need to rule out host/router/provider issues. Try ‘ping -6
>     www.google.com <http://www.google.com>’ on the host.
>
>     Aleksey
>
>     On 17 Jun 2015, at 09:44, Maarten Hoes <hoes.maarten at gmail.com
>     <mailto:hoes.maarten at gmail.com>> wrote:
>
>>     Hi,
>>
>>
>>     Thanks. Disabling ipv6 in the guest solves the issue.
>>
>>     Still, I dont understand why ipv6 shouldnt work ? My host os has
>>     both an ipv4 address and an ipv6 address, provided by DHCP with my
>>     internet provider's 'modem' (which has ipv4 and ipv6 access to the
>>     internet). In theory at least it should work, so I would still
>>     like to investigate further if anyone has any further suggestions.
>>
>>     Anyway, thanks for all the kind help by all.
>>
>>
>>     - Maarten
>>
>>
>>
>>     On Tue, Jun 16, 2015 at 9:51 PM, Aleksey Ilyushin
>>     <aleksey.ilyushin at oracle.com <mailto:aleksey.ilyushin at oracle.com>>
>>     wrote:
>>
>>         Hi,
>>
>>         It looks like the guest tries to reach www.google.com
>>         <http://www.google.com/> via IPv6 and never receives any
>>         replies. The problem may happen to be irrelevant to
>>         VirtualBox. Try disabling IPv6 in the guest.
>>
>>         Aleksey
>>
>>         On 16 Jun 2015, at 19:55, Maarten Hoes <hoes.maarten at gmail.com
>>         <mailto:hoes.maarten at gmail.com>> wrote:
>>
>>>         Hi,
>>>
>>>
>>>             I attached the gzipped capture to this message
>>>
>>>         At least I meant to, but seem to have forgotten. Here we go,
>>>         attachment included this time.
>>>
>>>
>>>         - Maarten
>>>
>>>         <virtuaboxnic1.pcap.gz>