Re: Q: Setting retries on the half-hour?

[Matti Aarnio <mea@utu.fi>]

	This problem is (as I understand) due to the generic asynchronous
	nature of the SMTP transmissions.  If your ISP is a non-bypassable
	focus of transmissions, things could be rather simple by spooling
	messages there into BSMTP/UUCP, and then hopping the batch to you.

	However appearance and disappearance of the target system in
	generic Internet has never been an easy to solve problem..

...
> Instead of expiring their timeouts artificially, how hard would it be
> for the scheduler to calculate the number of intervals needed to
> sychronise to a given time, and set the job's timeout to exactly that
> value; in other words, have the timeouts be determined automatically
> instead of strictly following the configuration file?  Of course, this
> means I've probably just volunteered myself to implement this feature
> ;-)

	I am uncertain as to how to describe the proper time to
	run queue -- like "at every hour at minutes 3, and 33" ...
	CRONTAB has a well-established format for that, though.

	The "timeout" I was thinking about is inside scheduler to
	implement, when some queue is to be attempted next time.
	There is another "timeout" -- message sending expiration.

	I still do think the best would be to have a system to
	signal scheduler, that it should immediately activate
	some thread/channel, instead of waiting until its next
	scheduled time.

	Such utility could be used from CRON, once the dialup
	connection is active, for example.  (Or from PPPD's
	ip-up script...  I am thinking in terms of Linux PPP,
	though the pppd is common for multiple platforms.)

...
> I agree, this would be complicated, at least for what I had in mind.
> The interesting thing about this particular problem is that I imagine
> more and more users will run into this, due to the proliferation of
> PCs running Linux/FreeBSD/NetBSD over a non-dedicated link.

	Have you looked at Linux diald ?  It will establish connection
	(per some control rules) at the time of the need.

> I guess one good solution exists now, although its expensive (at least
> for me): buy a router ($1000 US-$1500 US) that presents a dialup as a
> virtual Ethernet (something like an Ascend Pipeline 50?) that would
> connect transparently to your Internet service provider (ISP) whenever
> an outbound SMTP connection to a remote host takes place.  However,
> this solution would also require that your ISP implement dialup on
> demand at their site too, something I think most ISPs wouldn't be
> interested in.

	Hmm.. You mean from your ISP to yourself so that the ISP
	does dialing ?   I see why they are not very much interested
	in such a setup  :-)  (It is a question of billing...)

	Of course, alternate is to use leased line, the break-even
	price-point will appear soon with much active dialup time.

> --
> Dario Alcocer
> alcocer@netcom.com

	/Matti Aarnio <mea@utu.fi>