On 11/7/06 8:59 PM, "Scott Kitterman" <[EMAIL PROTECTED]> scribbled:
> On Tuesday 07 November 2006 22:07, Powers, Jot wrote:
>> On 11/7/06 7:08 PM, "Scott Kitterman" <[EMAIL PROTECTED]> scribbled:
> 
>>> I think that rejecting messages meets the goal that is stated here
>>> without adding risk or uncertainty.
>> 
>> We agree, if we can get that data phase rejection.  The problem that I see
>> is that most systems aren't setup to do that, and aren't willing to take on
>> the complexity of "mostly" accecpting before rejecting.
> 
> This may be what you meant, but it's my understanding that you have to accept
> the entire message and respond 550 to the final '.'.
> 
> There are timing issues associated with doing CPU intensive processing before
> queing the message that would have to be managed.  Is that where you see the
> complexity?

Yes, although it's been a long time since I've managed a site that was
mostly incoming email, so I'm probably not up to date on what the large mail
providers have to deal with.

>> As an admin at a large (non-spam) email site, that is, to put it mildly,
>> heavily phished, we would rather email that is not DK signed be dropped (ie
>> silently deleted) than "rejected" if my statements about rejection after
>> data are true.
> 
> I can understand that.
> 
> I think that reject or deliver (if only to a spam folder) is a reasonable
> approach.  Deleted might not be a bad fallback if rejection doesn't work out
> for some reason for some receivers.

My thoughts are that I know what problems deferrals cause me on the sending
side (due to new public IPs that aren't whitelisted), I imagine the problem
would be worse on the receiving side if a rejection was guaranteed never to
be delivered (ie mail accepted, and *GASP* a forged from header :)  ).  In
that case I would expect a "reject, then delete" policy would be in the best
interests of the receivers.

> I do know that there are large commercial receivers that are doing tasks more
> CPU Intensive than DKIM verification (e.g. virus scanning) during the SMTP
> session and doing it reliably, so I believe that while reject after DATA does
> have challenges, I think they are manageable.

In my experience, I/O is more of the problem than CPU, but I'd love to hear
what the receivers say.

-Jot
-- 
Jot Powers             <[EMAIL PROTECTED]>
Skype: jotebay

"Trimming quoted text in email leaves more room for you in heaven."
   -Ricardo Signes in irc://irc.perl.org/#perl

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