Patrick,

I believe we're making the same points and again we can agree to disagree on 
the value and risk of draft-ietf-regext-unhandled-namespaces.  I do need to 
clarify one thing, there was no specific changes needed on the client-side to 
support draft-ietf-regext-unhandled-namespaces other than ensuring that the 
draft-ietf-regext-unhandled-namespaces XML namespace is included in the login 
services.  Inclusion of the draft-ietf-regext-unhandled-namespaces XML 
namespace in the login services is not required of the client, but does 
indicate to the server that the client does support monitoring the EPP poll 
messages and general EPP responses for unhandled namespaces.  The other change 
that I implemented was to include tests that exercised the use cases outlined 
in draft-ietf-regext-unhandled-namespaces by explicitly removing XML namespaces 
from the login services and handling the lack of client support in the server 
for poll messages and general EPP responses.  Clients should be capable of 
parsing and marshaling the <extValue> element regardless of whether or not 
draft-ietf-regext-unhandled-namespaces is supported.  

The key change for the client is to recognize that support for a service is 
missing and to update the client to support it.  The approach taken with 
draft-ietf-regext-unhandled-namespaces enables the information to be returned 
without the chance of breaking a validating client that doesn't support the 
service, ensures that a poison message doesn't stop the processing of the poll 
queue, and informs the client that they don't support a specified service.  The 
extensibility of EPP provides the capability to address issues that were not 
foreseen at the time that the EPP RFCs were created, which is the case for 
draft-ietf-regext-unhandled-namespaces.    

-- 
 
JG



James Gould
Fellow Engineer
jgo...@verisign.com 
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703-948-3271
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Verisign.com <http://verisigninc.com/>

On 10/21/20, 5:26 PM, "regext on behalf of Patrick Mevzek" 
<regext-boun...@ietf.org on behalf of p...@dotandco.com> wrote:

    On Wed, Oct 21, 2020, at 15:56, Gould, James wrote:
    > 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.

    That is purely a judgment call.
    The specifications say: this part is filled with content from client.
    This is clear and non-ambiguous.

    Hence a client parsing it is expecting to see there... data it already sent
    since it is the client, per the specification. You can say it is a bad 
client
    if it starts to misbehave because it sees other things there, but you can't 
    also know or take into account all servers and clients out there, and their
    specificities.

    > 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. 

    Again, you take as granted that everyone will update their clients at the 
moment
    your specification becomes RFC (That won't happen as it doesn't happen for 
any RFC, no matter how good it is) or the fact that all clients work the
    same as yours.

    And for all clients not updated or doing things differently than yours, 
this draft may break them as soon as the EPP servers they connect to implement 
it.

    > 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. 

    Yes, in theory.
    In practice, deployments do not happen like that, unfortunately.

    I am just trying to give some data about past experiences.

    >  A draft can be defined to 
    > cover the usage of an existing element in the RFC for a specific 
    > feature,

    No, you are explicitly redefining usage as described in RFC 5730.

    It looks minor in your eyes, not in mine, so our vision will remain 
separate.

    > 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. 

    ... and not defined in RFC 5730 which is the problem for every client out 
there
    that won't or can't or not yet upgrade to your specification.

    > 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.  

    Yes, it does prohibit because it says "client provided" and you are putting
    things in it that are not "client provided".
    Your specification redefines core parts of the current EPP specification.

    And to be honest, one moment you say "RFC 5730 couldn't predict the need
    to handle undefined namespaces hence does not speak about them" (obviously)
    so that you can justify overriding one of its specification
    and here you say "RFC 5730 does not prohibit what this draft is trying to do
    (as if RFC 5730 could have known that in advance)". I believe this is one
    argument and its opposite so difficult to have both at the same time, but 
    maybe I am just getting at my limits in English, which is very possible.

    > 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.

    I am not saying otherwise and I sure don't expect a change because
    it is already presented as the best or unique solution on the problem, it 
    has been discussed extensively and to me this specific solution creates its
    own set of problems, hence my disagreement.

    If I am the only one seeing that the text redefines RFC 5730 in 
    different and incompatible ways, and the only one believing that not all 
clients will suddenly
    be upgraded to use this specification (as if all EPP servers out there will
    be updated...), then so be it, it does not really matter.

    Again, I am not trying to convince anyone, I know it won't happen,
    I just phrased my justifications on the problems I see.

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

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