[v6ops] Re: DHCPv6 PD in a multi-prefix environment

[David Farmer <[e-mail]>]

So, are you saying the SNAC router should use a GUA prefix in all cases and
expose the IOT devices to the Global Internet?

On Tue, Jul 23, 2024 at 9:55 PM Ted Lemon <[e-mail]> wrote:

> No, I mean can you describe a real-world scenario where this would happen.
> I get that you could configure a DHCP server to do this. The question is,
> when would someone configure the DHCP server that way?
>
> On Tue, Jul 23, 2024 at 7:49 PM David Farmer <[e-mail]> wrote:
>
>> I already did scenario A.3 in draft-ietf-snac-simple. It is appropriate
>> for the SNAC router to obtain a ULA prefix instead of a GUA prefix to
>> reduce the attack surface of the IOT devices.
>>
>> On Tue, Jul 23, 2024 at 9:33 PM Ted Lemon <[e-mail]> wrote:
>>
>>> Can you give us an example of a situation where such a decision would
>>> need to be made?
>>>
>>> On Tue, Jul 23, 2024 at 6:48 PM David Farmer <farmer=
>>> [e-mail]> wrote:
>>>
>>>> The classic ISP use case for DHCPv6 PD, as envisioned initially by
>>>> RFC3633 and integrated into RFC8415, typically expected a single prefix to
>>>> be delegated to a requesting router from the ISP. Meanwhile, many of the
>>>> draft-ietf-v6ops-cpe-lan-pd use cases probably expect a subdelegation from
>>>> this ISP provided prefix. Nevertheless, an RFC7084 CE Router may also have
>>>> a ULA prefix to subdelegate from, and a ULA prefix may be more appropriate
>>>> for some of the use cases. Not to mention, there may be prefixes from more
>>>> than one ISP or additional prefixes while renumbering.
>>>>
>>>> Should the delegating router in draft-ietf-v6ops-cpe-lan-pd advertise
>>>> subdelegations from all prefixes it may have and let the requesting router
>>>> choose one or more? How does the requesting router know which prefixes it
>>>> is appropriate to select in what circumstances? If the delegating router
>>>> doesn't advertise subdelegations from all prefixes, how does it know which
>>>> prefixes to advertise to which requesting routers?
>>>>
>>>> You can also ask the question from the opposite direction: How does the
>>>> requesting router solicit for a ULA prefix instead of a GUA prefix if that
>>>> is more appropriate for its use case?
>>>>
>>>> These questions came to mind while reading draft-ietf-snac-simple, as
>>>> it would seem reasonable to want the SCAC router to obtain a ULA prefix
>>>> from the delegating router and not a GUA prefix, especially in the scenario
>>>> described in A.3. However, similar questions exist for downstream RFC7084
>>>> or PD-per-device in a multi-prefix environment.
>>>>
>>>> Thanks.
>>>> --
>>>> ===============================================
>>>> David Farmer               Email:[e-mail]
>>>> Networking & Telecommunication Services
>>>> Office of Information Technology
>>>> University of Minnesota
>>>> 2218 University Ave SE        Phone: [phone]
>>>> Minneapolis, MN 55414-3029   Cell: 612-812-9952
>>>> ===============================================
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>>>>
>>>
>>
>> --
>> ===============================================
>> David Farmer               Email:[e-mail]
>> Networking & Telecommunication Services
>> Office of Information Technology
>> University of Minnesota
>> 2218 University Ave SE        Phone: [phone]
>> Minneapolis, MN 55414-3029   Cell: 612-812-9952
>> ===============================================
>>
>

-- 
===============================================
David Farmer               Email:[e-mail]
Networking & Telecommunication Services
Office of Information Technology
University of Minnesota
2218 University Ave SE        Phone: [phone]
Minneapolis, MN 55414-3029   Cell: 612-812-9952
===============================================