ietf-smtp
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Re: draft-klensin-rfc2821bis-04: VRFY and EXPN syntax

2007-07-14 17:24:54
On 2007-07-14 23:29:31 +0200, Markus Stumpf wrote:
On Sat, Jun 16, 2007 at 10:05:20AM +0300, Kari Hurtta wrote:
4.1.1.6.  VERIFY (VRFY)
4.1.1.7.  EXPAND (EXPN)

Does anybody know about any MTA actively using these today?
Is there any secenario (besides address harvesting) within which these
are still useful in todays email communication?

I don't think so. VRFY might be useful for SMTP address verification
(indeed there are people who maintain that using VRFY for that purpose
is ok but using MAIL FROM:<>/RCPT TO:<address> is abuse), but it's too
little supported and too unreliable for that.

As for EXPN, I don't think there is a valid use on unauthenticated SMTP
connections.


IMHO most MTAs support the commands but respond something like:
    252 send some mail, i'll try my best

Yes. When I did some experiments with SMTP callbacks some time ago, I
found that most MTAs return that (I wonder what advertising the VRFY
capability in the EHLO response and then returning a useless result is
supposed to accomplish ...), but even worse, some expected the email
address in angle brackets and some without, so you would get false
negatives unless you tried both ... Too much trouble for too little
gain.


Why not simply drop them completely?

Might as well.

        hp

-- 
   _  | Peter J. Holzer    | I know I'd be respectful of a pirate 
|_|_) | Sysadmin WSR       | with an emu on his shoulder.
| |   | hjp(_at_)hjp(_dot_)at         |
__/   | http://www.hjp.at/ |    -- Sam in "Freefall"

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