Re: [Jmap] Address Validation (was Re: Submission)

["Adrien de Croy" <[e-mail]>]

"two mechanisms to perform the same function is poor design"

Sorry I missed this one on the Mt Sinai tablets.

We are now and have throughout history been completely inundated with 
multiple designs and implementations of things for the same function. 
History has proven this to be a vital part of evolution.

Stating this is therefore by definition somehow "poor design" seems like 
an argument for never improving anything.

It could just as well be argued that if the first incarnation were not 
poor design there would be no need for the existence of (let alone 
proposals for) the second and subsequent.  So maybe with that 
interpretation you're right.

In any case validation upon submission of only local addresses is a long 
way short of validation prior to submission (during composition) of 
local and remote addresses, or at least even just allowing for the 
possibility of this.  It's too little too late.

Adrien


------ Original Message ------
From: "Chris Newman" <[e-mail]>
To: "Adrien de Croy" <[e-mail]>
Cc: "[e-mail]" <[e-mail]>
Sent: 22/04/2017 1:02:55 PM
Subject: [Jmap] Address Validation (was Re: Submission)

>On 20 Apr 2017, at 23:16, Adrien de Croy wrote:
>>>In article <emd3533c0d-dc08-45c3-801c-07972858ad64@bodybag> someone 
>>>write:
>>>>I'd love to see a mail client that does at least initial validation 
>>>>on
>>>>destination email addresses as they are added to the message, so 
>>>>that
>>>>errors in the addresses which can be resolved at that stage (e.g.
>>>>NXDOMAIN) can be raised with the email author before the mail is 
>>>>even
>>>>submitted.
>>>
>>>This is quite the can of worms.  It's easy enough to look up a domain
>>>and see if it has an A or an MX, but whatever you were planning to do
>>>to validate mailboxes will get you blacklisted as a listwashing
>>>spammer.
>>sure, I think there are fundamental issues with trying to go further 
>>than an A/MX for now, but if we built in a mechanism to verify 
>>addresses, it could be extended later, rather than being blocked off 
>>for all of eternity.
>>
>>Even A/MX would have some value.  Who knows what kind of trusted mail 
>>delivery infrastructure may come out in the future, at some stage we 
>>have to fix SMTP.  Forever is a long time.
>
>The present model for MUA mail address validation is to authenticate to 
>an IETF standard submission server, issue a MAIL FROM + RCPT TO + RSET. 
>Anyway, I support adding a feature in JMAP that does the equivalent of 
>performing this sequence of commands on the Submission server and 
>returns a 3-digit SMTP status code, optionally SMTP enhanced status 
>codes (see RFC 3463 section 3.2) and text string.
>
>This is quite extensible and I believe this specific functionality is 
>in-scope of the JMAP charter as Submission (RFC 6409) is explicitly 
>in-scope. Doing address validation this way is already quite powerful. 
>For example, if the submission server chooses to implement the SMTP 
>251/551 response codes for local users, the mail client gains the 
>ability to prompt the user to correct the address book entry for that 
>recipient.
>
>How much validation the submission server does then becomes a 
>quality-of-implementation issue (and there are, of course, 
>security/privacy issues). Future work would be to define additional 
>SMTP/Submit enhanced status codes for additional address validation, 
>but that's presently out-of-scope for the JMAP charter.
>
>The JMAP charter does not permit development of a new address 
>validation mechanism and I object to development of a new incompatible 
>validation mechanism on the grounds that having two mechanisms to 
>perform the same function is poor design, when a full-standard 
>mechanism to do address validation already exists. I support mapping 
>the existing Submission validation mechanism to JMAP in a way that 
>preserves all the semantics of the existing mechanism.
>
>   - Chris
>
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