Patrick,

I provide me responses embedded below.

-- 
 
JG



James Gould
Fellow Engineer
jgo...@verisign.com 
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On 10/21/20, 12:22 PM, "regext on behalf of Patrick Mevzek" 
<regext-boun...@ietf.org on behalf of p...@dotandco.com> wrote:

    James,

    On Mon, Oct 19, 2020, at 08:31, Gould, James wrote:
    >     Considering a default opt-in puts all currently existing EPP 
    > clients at risk.
    > 
    > JG - draft-ietf-regext-unhandled-namespaces addresses an 
    > interoperability issue with the server returning extensions that the 
    > client specified is not supported.  The <extValue> element is already a 
    > feature supported by RFC 5730, so this is not something "forced on 
    > them".  

    You are misreading me or misquoting me.
    What your draft forces on is the use of extValue
    as NOT described by RFC 5730 hence putting all current clients at risk,
    because you "silently" change some core expectations of RFCs 5730+.

    I know the problem you are trying to address (I even think I was one of the 
people
    raising it in the first place but note that in 20 years or more that EPP 
exists, it obviously 
    did not move people so much even if it is a real problem),
    I am just trying to explain that this draft
    creates an interoperability problem by just changing the semantics of RFC 
5730
    without letting clients decide if they want it or not, they are forced by 
the server,
    hence this default opt-in migration of the current park of EPP clients will
    create problems.

JG - I'm not clear of the risk of returning information in the <extValue> 
element to clients.  There won't be a schema validation error like the case of 
returning a non-supported extension to a validating client.  There won't be a 
marshaling error for the client, since unmarshaling the <extValue> in the 
<result> element should already be supported.  The most likely issue is that 
the client will ignore the information, which does not pose an operational 
risk.  I've implemented draft-ietf-regext-unhandled-namespaces on the server 
side and in a validating client within the Verisign EPP SDK, and I don't see 
any potential risk for the client.  Martin implemented 
draft-ietf-regext-unhandled-namespaces in a Production server and hasn't come 
across any reported client-side issues.  A server can choose to implement 
draft-ietf-regext-unhandled-namespaces and when doing so should notify the 
clients ahead of time, so this is not something that would be thrown onto 
clients without notice.      

    > This is not a new feature from a protocol 
    > perspective that will cause an interoperability issue.  

    It is, because extValue is defined as containing *client* data that created 
an error,
    and you are stuffing it with *server* data.

    Plus the return code of 1000 + extValue case that I tried to explain, which 
doesn't seem to me
    really covered by existing RFCs, so you are just redefining things, hoping 
that
    all clients immediately will just implement your draft and hence everything 
is fine
    but unfortunately that is not what is going to happen...

    Maybe all of this is fine, redesigning EPP from scratch today, I could agree
    with all this. But I am just pointing out that specifications already exist
    and are NOT aligned with the way you try to use them in this draft. This is 
the
    interoperability problem, not the features themselves, the fact that you add
    them on top of things where they do not fit 100%.

JG - RFC 5730 did not foresee the issue associated with returning poll messages 
to clients that don't support the extensions in the poll message.  We discussed 
this at length at multiple REGEXT meetings, and the best solution to this 
problem is defined in draft-ietf-regext-unhandled-namespaces.  A draft can be 
defined to cover the usage of an existing element in the RFC for a specific 
feature, which in this case is to enable servers to comply with the EPP RFC for 
poll messages and when there is the need to return additional information to 
the client (e.g., DNSSEC information).      

    > There is no normative language in RFC 5730 that would 
    > prohibit the use of <extValue> for the use case covered in 
    > draft-ietf-regext-unhandled-namespaces.   

    I believe there is and I quoted you so. Note the mention of 
"client-provided element", but
    you seem to just ignore that point.

    A specification can not list everything prohibited. It lists what is allowed
    (and it says clearly "client-provided element") and then as a safe view you 
can expect
    the rest not to be allowed.

JG - Yes for an error it makes sense to include the "client-provided element".  
The case defined in draft-ietf-regext-unhandled-namespaces is not an error and 
the use of the <extValue> element for this use case is defined in 
draft-ietf-regext-unhandled-namespaces.  The description of the element does 
not prohibit the use of the element to address a specific well-defined problem 
solved by draft-ietf-regext-unhandled-namespaces.  

    >     There may be clients out there that will consider value/extValue 
    > only for error
    >     return codes (>=2000) and will get confused when getting back 1000 
    > but with extValue
    >     as this draft calls for.
    > 
    > JG - RFC 5730 did not envision this case, which is the point with the 
    > standardization of draft-ietf-regext-unhandled-namespaces.  

    Which is the core of the problem and the interoperability risk.
    You redefine core parts of RFC 5730 without taking into accounts that 
clients
    may not be aware of your change (your draft) and hence will have problems
    if the server forces that new view on them, without any possible 
negotiation.
 
    At this point it seems we are just repeating our own arguments on both side,
    so I don't think either will move their position and we have to keep our
    disagreement, which is fine.

    I wanted to record my disagreement on this draft during WGLC, that is all.

JG - We can agree to disagree on the value and risks associated with 
draft-ietf-regext-unhandled-namespaces.  The Document Shepherd can include a 
reference to your disagreement in his writeup, but I don't believe there is 
consensus to make a change.

    -- 
      Patrick Mevzek
      p...@dotandco.com

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