Re: [dhcwg] I-D Action: draft-ietf-dhc-dhcpv6-pd-relay-requirements-00.txt

[Timothy Winters <[e-mail]>]

Hi Ian,

  We've seen it on our setups when we reboot a device and forget about
connection to a LAN clicent.   Oddly we aren't trying to test the
forwarding loop so I would say it happens.

I think that text resolves my issue perfectly.

~Tim

On Wed, Apr 8, 2020 at 11:33 AM <[e-mail]> wrote:

> Hi Tim,
>
> Have you seen this in the wild?
>
> What about the following:
>
>    R-4:    If the relay has an existing route for a delegated prefix via
> an interface, and receives ingress traffic on this interface with a
> destination address from the delegated prefix (not configured on the
> relay), then it MUST be dropped.
>
> Thanks,
> Ian
>
>
> On 8. Apr 2020, at 16:38, Timothy Winters <[e-mail]> wrote:
>
> Hi Ole,
>
> I think the issue in all of these cases is the CPE doesn't know it had the
> prefix previously.  So 3633 won't cover this case, as to the CPE it just
> seems like IPv6 packets.  It routes them out it's default route, which
> happens to be the same interface it got them.
>
> ~Tim
>
> On Wed, Apr 8, 2020 at 10:29 AM Timothy Winters <[e-mail]> wrote:
>
>> Hi Ole,
>>
>> We have a rule for this when it's delegated to the CPE, WPD-5 to
>> blackhole PDs not assigned.  In this case the CPE had no idea it had it.
>>  G-3 disallows LAN to WAN forwarding before getting an address.  I think
>> this case is WAN to WAN forwarding.   It's not in 7084 to my knowledge, as
>> for 3633 I'm not so sure about.  Let me have a look.
>>
>> ~Tim
>>
>> On Wed, Apr 8, 2020 at 10:12 AM <[e-mail]> wrote:
>>
>>> > Sounds like a useful issue to try to address – the DHC connection is
>>> because of the DHCP issues.
>>> >
>>> > And, I assume looping occurs because packets cycle between SP router
>>> and CPE until TTL/HOP expires?
>>> >
>>> > Do you have a suggestion as to what the CPE should do in this case?
>>> For example, are you suggesting that the CPE drop received traffic (except
>>> for DHCP and perhaps some other limited traffic addressed to it)?
>>>
>>> A CPE should never provide transit.
>>> I.e it should never forward a packet received on it's WAN interface back
>>> out the WAN interface.
>>>
>>> A more specific rule for that is in 7084 and possibly in 3633, requiring
>>> a blockhole route on the requesting router for the delegated prefix.
>>>
>>> Ole
>>>
>>>
>