Fri, 9 Aug 1996 09:09:09 PDT
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On Wed, 7 Aug 1996 19:24:29 -0700 Mario Rups <[log in to unmask]> wrote:
> > I heard that AOL crashed today. Has anyone heard anything? I run
> > four lists off of AOL's LISTSERV site and haven't received a response
>
> It even hit the evening news -- since 0400 EDT this morning, they said.
> And HERE is where I get VERY grateful for AOL's habit of rolling all
> error messages into one per message as opposed to one per subscriber.
>
> Good luck, AOL, I suspect you're going to be in for a LOT of flack.
Why? When a system "crashes", several things happen:
- 1. users cannot login -- and they complain,
- 2. E-mail originating from AOL is not delivered,
and maybe 1% of the recipients notice the lack of E-mail,
- 3. E-mail destined for AOL cannot be delivered by SMTP-clients.
Fortunately, SMTP is "robust" -- it was *DESIGNED* to include the possibility
that the receiver's SMTP-server may not be functioning at the time that the
sender's SMTP-client attempts to make a connection.
So, unless the AOL outage lasts for a *LONG* time, the SMTP-client will just
keep "silently" attempting to make a connection. After a *LONG* time,
say 1 day or 3 days or 7 days, the SMTP-client may either issue a "temporarily
unable to deliver" message, or a "permanently unable to deliver" message.
It's only at this point that the non-delivery is announced to the author
of the message.
In general, if an SMTP-server is "down" for a *SHORT* period of time,
the sender of the E-mail will get *NO* notification from the SMTP-client
that the mail-delivery was not "instantaneous".
A tempest in a tea-pot?
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