[EAI] Comments on draft-ietf-eai-downgraded-display-01

[SM <sm at resistor.net>]

Hello,

These comments are for draft-ietf-eai-downgraded-display-01.  Please 
consider them as "I read the document".

In Section 2:

  "An "UTF8SMTP message" is an Email messages expanded by [RFC5335]."

There is a typo for "Email message".

In Section 4:

     "Apply Email header fields downgrading defined in section 5
      of [I-D.ietf-eai-downgrade] to the output of Step 2 without re-
      generating "Downgraded-" header fields."

This document describes the restoration methods.  I read the above as 
apply downgrading again as defined in RFC 5504.

      "Don't change "Downgraded-Mail-From" and "Downgraded-Rcpt-To"
      header fields because they do not have their original header
      fields."

You are not changing these header fields as they correspond with a 
SMTP envelope, i.e. the original is not a header field.

In Section 5:

  "While information in any email header should usually treated with
   some suspicion, current email systems commonly employ various
   mechanisms and protocols to make the information more trustworthy.
   For example, an organization's boundary MTA can modify From: lines so
   that messages arriving from outside the organization are easily
   distinguishable from internal emails. As a result of rewriting, the
   Downgraded-From header field may not be decoded."

Modifying the "From:" lines does not make the information more 
trustworthy.  It is more of a hack to get around the limitations of 
the MUA.  Please see whether the "decoding failure" (last sentence in 
the paragraph above) note would be more appropriate in Section 4 
instead of Section 5.  The Security Considerations section needs some 
more thought in my opinion.

Regards,
-sm