Re: Comments on draft-gellens-on-demand-03.txt

["Jeff Stephenson" <jeffstep@xxxxxxxxxxxxx>]

-----Original Message-----
From: Randall Gellens <Randy@xxxxxxxxxxxx>
Date: Friday, March 20, 1998 3:08 PM


>At 10:45 AM -0800 3/20/98, Jeff Stephenson wrote:
>
>>1)  I still think that ODMR should be done on the SMTP port....
>
>There are timing issues as well as architectural issues that make that
>undesirable...

Timing issues?  How so?  If you're refering to sending and receiving at the
same time, it's just as easy to open two connections to port 25 (sending on
one, issuing ATRN on the other) as it is to connect to 25 and xxx.  As to
architectural issues, I don't think that the fact that there are some SMTP
implementations for which this might not be as easy to implement within SMTP
as it would be to implement as a separate service justifies another
port/protocol.  Given that ETRN is seen as an extension to SMTP, ATRN should
be also.

>>2) I don't think there should be domain arguments on the ATRN command....
>
>The domain argument is now optional...

>From my reading, the domain is optional for the client (customer) but not
the server (provider) side of the protocol; the server still needs to be
able to validate any domains that appear in a command.  I'm not sure what
this added complexity buys anyone.  It seems to me that the situations in
which a customer would want to dequeue mail for a subset of their domains
are pretty limited, and the rare case could be handled by different
authorization IDs.

>>3) I don't see the lack of queued mail as an "error" condition worthy of a
>>450 response....
>
>I don't see it as terribly important either way.  An error response
>makes it perhaps a bit easier to know there won't be a new connection
>coming back, so you can drop the line.

I don't think there's much (if any) efficiency to be gained here.  Using C
(customer) and P (provider), the two options seem to be

   C: ATRN
   P: (... let's see if there's mail queued for this guy ...)
   P: 450 Nothing for you
   C: QUIT

or

  C: ATRN
  P: 250 Connection turned
  P: (... let's see if there's mail queued for this guy ...)
  P: QUIT

I prefer the latter, because it clearly separates the case of no mail
(meaning "try again at your scheduled time") from a temporary error like the
authorization ID -> domain mapping database being unavailable (meaning "I'm
having problems - try a little later").  Especially in the case of a
customer scheduled to dial up only once a day, there may be significant
differences in the time the host should wait before retrying.

-- jeff