Re: Intent to revive "expires" header from draft-ietf-mailext-new-fields-15

On Thu, 2008-07-24 at 09:49 -0400, Keith Moore wrote:
> Jeff Macdonald wrote:
> > 
> > On Wed, 2008-07-23 at 08:16 -0400, Keith Moore wrote:
> >> "MUAs, Message Stores, and MTAs, MUST NOT delete a message on the basis 
> >> of an Expired header field unless given explicit instructions to do so 
> >> by the recipient."
> > 
> > I find it very desirable to have MTAs generate a bounce if the message
> > is older than the Expired header.
> 
> (What does it mean for a message to be older than a header contained 
> within the message?  I assume you mean "... if the date in the Expired 
> header is after the current date.")

yep

> Now it might also be useful if there were a MTS feature that would let
> a 
> sender say "don't bother delivering this message if you can't get it 
> there before <date>".  But I don't think that's what we're talking
> about 
> here.  (and if there were such a feature it should be implemented in 
> SMTP rather in the message header).

it is what I was thinking and Ned rightly pointed out that DELIVERYBY
handles what I was looking for.

The only thing I don't like about that extension is it really needs a
3rd mode. If I understand the RFC correctly:

* mode R
means bounce message even if the DELIVERYBY time hasn't expired when
delivering to an MTA that doesn't support DELIVERYBY

* mode N
means attempt to deliver when time has expired but notify the sender

Neither of these does what I'd like. I need a mode that is like R but
will deliver to MTAs that do not support DELIVERYBY. This way the
originating can expire messages and doesn't have to worry if the rest of
the world supports DELIVERYBY.

Unless of course I am mis-understanding section 4.1.4. I'm not sure how
a sending MTA knows it is sending email to a relay. I'm assuming all
receiving MTAs could be a relay.


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