[comp.protocols.iso.x400] Fw: Away-service Away-service

fair@UCBARPA.BERKELEY.EDU (Erik E. Fair) (05/18/88)

There is a very simple way to prevent "I am on vacation" messages
from going to mailing lists - the agent should never reply to a
message which does not have your address somewhere in the recipient
list in the headers. Since mailing lists are never expanded in the
headers, you win.

	Erik E. Fair	ucbvax!fair	fair@ucbarpa.berkeley.edu

huitema@mirsa.inria.Fr (Christian Huitema) (05/20/88)

> Hello Jacob ...  Your scheme, shown here ...
> 
> > The best solution would be to make the "I am away"-messages into some
> > kind of notification, not an ordinary message.  Then an intelligent 
> > receiving system could recognize them as such and handle them
> > appropriately.  
> 
>  ...  puts the burden on every UA anywhere in the net to undo the error
> of your AWAY-MSG generator which is not caring how many copies of the
> same message it sends to the same recipient.  I cannot in any way
> condone such blatant lack of concern and shifting of responsibility from
> the place that knows what is going on and can easily deal with it, to a
> place that does not know what is going on and has great difficulty
> dealing with the consequeces.  

It should be obvious that "I am away" messages should not be sent more than
once to the same recipient. However, Jacob's suggestion does have a practical
interest. Suppose the person which is luckily cruising the Carribeans for 2
monthes is a member of several distribution lists: all members of all these
lists, often the same persons, will receive the "I am away" notification..
By sending (once) the "away message" or other auto answers as specially
typed messages (e.g. user level acknowledgments), one gives the opportunity
to the lists to adopt a special treatment, e.g. dropping them rather than
broadcasting.

Christian Huitema

galvin@TWG.COM (James M Galvin) (05/20/88)

> 	There is a very simple way to prevent "I am on vacation" messages
> 	from going to mailing lists - the agent should never reply to a
> 	message which does not have your address somewhere in the recipient
> 	list in the headers.

> Sorry, this sounds nice but I just don't believe it in practice.

> How do I detect "my address" in the headers?  There are umpteen different
> machines I have guest logins on, and the mail might have gone to any of
> them.

	[ ... deleted lots of examples of mailboxes ... ]

Maybe I am missing something, but if a message is getting delivered to
a given account, then either the account name and the name of the local
machine appear somewhere in the headers or they don't.  If they do then
you don't send an "away service" message, otherwise you do.

If you have many accounts which redistribute received mail to a central
one, there still is no problem if the redistribution CORRECTLY includes
the redistributed address.  Notice I said redistribute, not forward.  You,
of course, know the distinction.

Therefore, Erik's solution still holds.  What am I missing?

Jim

mark@cblpf.ATT.COM (Mark Horton) (05/21/88)

	Maybe I am missing something, but if a message is getting delivered to
	a given account, then either the account name and the name of the local
	machine appear somewhere in the headers or they don't.  If they do then
	you don't send an "away service" message, otherwise you do.
	
	If you have many accounts which redistribute received mail to a central
	one, there still is no problem if the redistribution CORRECTLY includes
	the redistributed address.  Notice I said redistribute, not forward.
	You, of course, know the distinction.

It could be that I just misunderstand the distinction.  To me, "redistribute"
is something you do to a mailing list, and "forward" is something you do
for an individual.  If you're saying that redistribution implies expanding
all the names in the header, then I don't follow you at all.  It seems the
other way around to me.

So I'll assume you're saying that mailing lists should keep the name
of the list in the header, while personal forwarding (including things
like postmaster@somewhere) get rewritten with the new name.

The problem is that all the forwarding software I'm familiar with does
not rewrite the headers to take the expansion in to account.  In fact,
forwarding and mailing lists are done with the same mechanism, forwarding
is just a mailing list with only 1 (sometimes 2 or 3) names on it.

Even if it did rewrite it, it's quite common to use a local route in
a forwarding address:
	Forward to cblpf!mark
is on several machines.  So checking for my own name is nontrivial.
(Also, there's no way to update every machine to rewrite headers,
lots of those machines out there run software that doesn't even know
what a header is!  Rewriting is hard and dangerous.)

	Mark

mark@cblpf.ATT.COM (Mark Horton) (05/24/88)

So, Jim, do you have an implementation running (or prototyped) that
can look at the header of a typical piece of mail and tell if "my
address" is in there somewhere?  It sounds like a pretty hard
problem to me.

	Mark