Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83; site uwvax.ARPA
Path: utzoo!watmath!clyde!akgua!mcnc!decvax!harpo!seismo!uwvax!dave
From: dave@uwvax.ARPA
Newsgroups: net.mail
Subject: Re: the mail must go through
Message-ID: <257@uwvax.ARPA>
Date: Sun, 13-May-84 09:48:18 EDT
Article-I.D.: uwvax.257
Posted: Sun May 13 09:48:18 1984
Date-Received: Mon, 14-May-84 07:03:40 EDT
References: <1805@mit-eddie.UUCP>
Organization: U of Wisconsin CS Dept
Lines: 39

> Erik Fair says that if ARPANET mail tranfer fails (due to unavailable
> ARPANET service), a message sent to
>     ...seismo!hao!hplabs!....!sri-unix!foo@ucl-cs.arpa
> will be returned to the sender.
>
> This is unacceptable if UUCP service from seismo to hao is available.
>
> Remember the adage of the mailman ...
> "Neither rain nor snow nor dead of night ...
>  Shall keep these couriers from their flight."  (paraphrased)
>
> This should apply to electronic mail also.  Do YOU think that if
> airplane service is unavailable at the moment, transatlantic mail is
> returned?  Is your local mail returned if the mailman's mail truck
> breaks down?  Of course not.

Sendmail (and ARPAnet) have two ways for mail to fail, temporary (analgous
to your mail truck breaking down) and permanent (like mailing to the
empty lot down the street).  If the mail fails because of an incorrect
address, it should be returned.  Period.

> Solution:  Have sendmail take the other route if the higher-priority
> route fails,

It doesn't matter if seismo can talk to hao, as that isn't what the person
said to do (does the mailman know that when someone mailed to that empty
lot, they really meant to send it to you?).

> or (better idea) have the message queued at seismo for
> later delivery until seismo's ARPANET service comes back up.

This is the way ARPAnet mail works already.  There is generally a three
day timeout (sometimes longer) on a message before mail is returned because
of a transmission problem.  That timeout is necessary too -- what if the
receiving host is permanently down?
-- 
Dave Cohrs @ wisconsin
...!{allegra,heurikon,ihnp4,seismo,sfwin,ucbvax,uwm-evax}!uwvax!dave
dave@wisc-rsch.arpa