Re: [v6ops] A common problem with SLAAC in "renumbering" scenarios

Christian,

The router cannot in its RPF check determine the reason for the wrong source address. If its spoofed or a previously valid address. Therefore code 5. 

Ole

> On 3 Feb 2019, at 21:10, Christian Huitema <huitema@huitema.net> wrote:
> 
> If the source address is allocated from a deprecated prefix, or an
> unknown prefix, the router cannot forward the packet. The router should
> send an ICMPv6 message, but from my quick reading of the RFC I could not
> find a code that said "the destination is unreachable because you are
> using a source address allocated from a deprecated prefix." The closest
> would be "Code = 5, source address failed ingress/egress policy", but
> that feels like an approximation.
> 
> An appropriate error code would help the source device might take some
> corrective action, like for example solicit an RA and configure an
> address with an up-to-date prefix. A specific connection might fail, but
> by the time little Johnny tries again a new source address would be
> available and the cat video will play fine. That seems a lot less
> frustrating than calling ISP support...
> 
> -- Christian Huitema
> 
>> On 2/3/2019 9:45 AM, JORDI PALET MARTINEZ wrote:
>> Agree. Just wanted to clarify that assertion, as I've heard it too many times.
>> 
>> AVM/Fritzbox, if I recall correctly is one of the very very very few vendors that write the prefix in the flash ...
>> 
>> Regards,
>> Jordi
>> 
>> 
>> 
>> -----Mensaje original-----
>> De: Brian E Carpenter <brian.e.carpenter@gmail.com>
>> Fecha: domingo, 3 de febrero de 2019, 20:41
>> Para: JORDI PALET MARTINEZ <jordi.palet@consulintel.es>
>> CC: "v6ops@ietf.org WG" <v6ops@ietf.org>, 6man WG <ipv6@ietf.org>
>> Asunto: Re: [v6ops] A common problem with SLAAC in "renumbering" scenarios
>> 
>>>    On 2019-02-04 06:46, JORDI PALET MARTINEZ wrote:
>>>    The RIPE document does not recommend it. In Germany, that's the expected
>>>    default.
>>> 
>>> ---->  This is not correct, in the context of another mailing list, a few day ago, some people (including people from Germany) confirmed that this is not true for Germany, neither there is any law or anything similar that requires dynamic prefixes.
>> 
>>    It doesn't matter. The objective fact is that getting a new prefix after a CPE reboot, or after a DSL disconnect/reconnect, or every 24 hours, is common, and not just in Germany.
>> 
>>    Not that I've ever had any stale address problems as a result, even at a time when I was getting multiple ADSL disconnects per day due to a line fault. So with a FritzBox and Windows hosts, the "common problem" simply wasn't a problem.
>> 
>>       Brian
>> 
>> 
>> 
>> 
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