Subject: [apps-discuss] Gen-ART review of draft-ietf-appsawg-malformed-mail-09

From: "Black, David" <[email-masked]>
Date: Fri, 1 Nov 2013 21:32:23 -0400

I am the assigned Gen-ART reviewer for this draft. For background on
Gen-ART, please see the FAQ at

<http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>.

Please resolve these comments along with any other Last Call comments
you may receive.

Document: draft-ietf-appsawg-malformed-mail-09
Reviewer: David L. Black
Review Date: November 1, 2013
IETF LC End Date: October 29, 2013
IESG Telechat date: November 21, 2013

Summary: This draft is basically ready for publication, but has nits that
should be fixed before publication.

This draft discusses common errors in mail message syntax and provides
useful guidance on handling them.  The draft is well written and likely
to be of significant value to implementers.

Most of my comments relate to clarity, but none of them seem important
enough to be characterized as issues that really have to be fixed,
although the sloppy terminology usage in Sections 7.1.* comes close.

I apologize for this review appearing slightly after the end of IETF
Last Call - there is too much going on in the weeks immediately before
this IETF meeting.

Nits/editorial comments:

The word "naked" is used a few times to refer to something that occurs in
isolation, without enclosure in another construct, e.g., a naked CR.  This
idiomatic use of "naked" should be explained before it is used.

In Section 1.1, I have always heard Postel's law as:
	- Be conservative in what you send, and
	- Be liberal in what you accept.
The change from "do" in this draft to "send" (above) seems useful, as
it should help focus the discussion in the second paragraph of Section
1.1 - Postel's law, as I have understood it, has never blessed anything
remotely resembling there being "no limits to the liberties that a
sender might take."

Section 5's section title "Mail Submission Agents" doesn't seem to be
connected to its MHS and MTA content.  It would be useful to add a
sentence to remind readers, including this one ;-), of what Mail
Submission Agents are.

Sections 7.1.* offers degrees of advice qualified by "safely", "usually",
"reasonably" and "should".  There appear to be only two concepts:
	- "safely": Do this all the time.
	- "usually", "reasonably", "should": This is the recommended course
		of action, but there may be exceptions.
While RFC 2119 is not intended for Informational documents, this is an
example of the sort of sloppiness that RFC 2119 is intended to clean up.
At the very least, the use of three words for essentially the same concept
is poor form, and RFC 2119 can be used in an Informational document when
appropriate caveats are provided in the terminology section that references
it.

In Section 7.1.4, "Likewise" is not a good way to associate the second
example with the first, because it handles the missing parenthesis in a
rather different fashion (adds quotes instead of inserting the missing
parenthesis character).

In Section 7.7, the first use of "8bit" occurs in "8bit material" but some of
the subsequent occurrences omit the word "material" - that word should be
used with all occurrences.

idnits 2.13.00 generated a couple of warnings about obsolete references:

  -- Obsolete informational reference (is this intentional?): RFC 1113 (ref.
     'PEM') (Obsoleted by RFC 1421)

  -- Obsolete informational reference (is this intentional?): RFC  733
     (Obsoleted by RFC 822)

In both cases, the reference appears to be intentional, and the warning
should be ignored.

Thanks,
--David
----------------------------------------------------
David L. Black, Distinguished Engineer
EMC Corporation, 176 South St., Hopkinton, MA  01748
+1 (508) 293-7953             FAX: +1 (508) 293-7786
[email-masked]        Mobile: +1 (978) 394-7754
----------------------------------------------------

---

From: "Murray S. Kucherawy" <[email-masked]>
Date: Wed, 6 Nov 2013 16:48:55 -0800

I think I'm going to request creation of my own private Directorate.  David
seems to get all my Gen-ART reviews, and we could possibly do some
optimizing here.  :-)

> idiomatic use of "naked" should be explained before it is used.

Fixed; just used "isolated" again.

> remotely resembling there being "no limits to the liberties that a

There are a bunch of versions.  See:

http://en.wikipedia.org/wiki/Jon_Postel#Postel.27s_Law

Some of them say "do", some say "send".  Perhaps the most authoritative one
is here, in Section 1.1.2:

http://tools.ietf.org/html/rfc1122

It says "send".  I'll make that a reference and adjust.

I concur that the Law doesn't bless the extremes, but I believe the email
community has (deliberately or through ignorance) gone there, which is
largely the point of this work.

> sentence to remind readers, including this one ;-), of what Mail

The final sentence of that paragraph specifies what it does, but I see your
point about the disconnect in terminology.  Will adjust to tie it all
together.

> appropriate caveats are provided in the terminology section that references

Earlier versions of this draft looked roughly like an applicability
statement, and thus had RFC2119 language throughout.   We decided that, as
you point out, it's mostly advice, and not a way of establishing a
capability within Internet Mail, which would be more like what an
applicability statement is for.

I'm thus inclined not to backtrack, but merely satisfy your "At the very
least" clause.

> rather different fashion (adds quotes instead of inserting the missing

Removed.

> used with all occurrences.

Fixed.

> In both cases, the reference appears to be intentional, and the warning

Correct; I'll make sure the AD sees this.

Thanks!

-MSK

---

From: Barry Leiba <[email-masked]>
Date: Wed, 6 Nov 2013 19:59:23 -0500

> Earlier versions of this draft looked roughly like an applicability
statement, and thus
> had RFC2119 language throughout.   We decided that, as you point  out,
it's mostly
> advice, and not a way of establishing a capability within Internet Mail,
which would
> be more like what an applicability statement is for.
>
least" clause.

I'm more inclined to leave it alone:
This is not conformance language at all, and isn't meant to be.  It's mild
advice about how one might handle bad situations.  We could be consistent,
and pick one word.  Or we can leave the document less stilted and have it
read better.  We specifically don't *want* to be precise, here, about the
strength or *exact* meaning of the advising words.

Barry

---

From: "Black, David" <[email-masked]>
Date: Wed, 6 Nov 2013 20:01:16 -0500

> I think I'm going to request creation of my own private Directorate.  David seems to get all my Gen-ART reviews,
> and we could possibly do some optimizing here.  :-)

Luck of the draw :).

All of your suggestions are fine, and in Section 7.1.*, picking a single word for "usually", "reasonably" and "should" will definitely suffice - I might suggest scanning the rest of section 7 for consistent use of terminology to express levels of recommendations.

Thanks,
--David

From: Murray S. Kucherawy [mailto:[email-masked]]
Sent: Wednesday, November 06, 2013 7:49 PM
To: Black, David
Cc: [email-masked]; [email-masked]; General Area Review Team ([email-masked]); Barry Leiba ([email-masked]); [email-masked]; [email-masked]
Subject: Re: Gen-ART review of draft-ietf-appsawg-malformed-mail-09

I think I'm going to request creation of my own private Directorate.  David seems to get all my Gen-ART reviews, and we could possibly do some optimizing here.  :-)

On Fri, Nov 1, 2013 at 6:32 PM, Black, David <[email-masked]<mailto:[email-masked]>> wrote:

Nits/editorial comments:

http://en.wikipedia.org/wiki/Jon_Postel#Postel.27s_Law
Some of them say "do", some say "send".  Perhaps the most authoritative one is here, in Section 1.1.2:

http://tools.ietf.org/html/rfc1122
It says "send".  I'll make that a reference and adjust.
I concur that the Law doesn't bless the extremes, but I believe the email community has (deliberately or through ignorance) gone there, which is largely the point of this work.

The final sentence of that paragraph specifies what it does, but I see your point about the disconnect in terminology.  Will adjust to tie it all together.

Earlier versions of this draft looked roughly like an applicability statement, and thus had RFC2119 language throughout.   We decided that, as you point out, it's mostly advice, and not a way of establishing a capability within Internet Mail, which would be more like what an applicability statement is for.
I'm thus inclined not to backtrack, but merely satisfy your "At the very least" clause.

Removed.

Fixed.