Re: MSGTRK pre-drafts

tony> Good points:

tony> can administer message tracking server separately
tony> can do referrals to another server that is ONLY running MTQP server

* Off loads the tracking work from the mail server.
* There isn't a one to one match between MTA and tracking server.  For
  example, consider a delivery to example.com which has the DNS records:

	example.com.		IN	MX 10	smtp.example.com.
	smtp.example.com.	IN	A	10.1.1.1
	smtp.example.com.	IN	A	10.2.2.2

  The message could go to either server.  When tracking time comes, you
  don't know if the message went to 10.1.1.1 or 10.2.2.2 so holding the
  track server inside the SMTP protocol doesn't gain you anything.  There
  would be one tracking server, that gathers information from both 10.1.1.1
  and 10.2.2.2 in order to answer tracking requests for the name
  "smtp.example.com".

tony> Bad points:

tony> another protocol, another port
tony> need to administer two servers now instead of just one
moore> need to keep msgtrk servers in sync with MTAs.

In response to Keith's bad point, yes, that is true but not a reason to
include it within the SMTP protocol.  That argument would mean that SMTP
should do POP and IMAP as well since the final delivery MTA which handles
local delivery to a mailbox and the POP server which reads mail from a
mailbox must be kept in sync.  Use compatible implementations doesn't
require a single protocol.