Re: Fwd: New Version Notification for draft-crocker-email-deliveredto-05.txt

On Thu 05/Aug/2021 04:16:40 +0200 Dave Crocker wrote:
> This has changes intended to cover the existing use of the field.


I read the draft anew.  Some nits/ notes/ questions below:


*3.  Delivered-To*

s/am email delivery/an email delivery/.

The new syntax looks puzzling:

    "Delivered-To:"  FWS *phrase Mailbox *phrase CRLF
                     ; Mailbox is from [SMTP]

The presence of phrases around the Mailbox makes this field difficult 
to parse.  Without angle brackets, the presence of an unquoted "@" 
being the only difference.  It is puzzling because phrase usage is 
neither discussed nor exemplified, and IME not seen in the wild.


*5.  Security Considerations*

I'd explicitly note that users concerned abut divulging their final 
recipient address should be wary about forwarding messages as 
attachment, e.g. when complaining about spam, because the topmost 
Delivered-To:'s can betray secret addresses.  How about recommending 
that MUAs provide a tool to remove that info?


*7.  Experimental Goals*

It is not clear whether implementations that are already recording 
Delivered-To: into messages but not exactly as specified in the I/D 
are supposed to change their code in order to comply rather than 
comment to the mailing list about their discrepancy.


Best
Ale
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