[H-GEN] Humbug machine problems and lost email

Greg Black gjb at gbch.net
Tue Sep 24 06:21:39 EDT 2002


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Robert Brockway wrote:

| On Tue, 24 Sep 2002, Greg Black wrote:
| 
| > The point of my message is that this has not happened.  Messages
| > that were sent to gjb at humbug.org.au have not been delivered
| > (yet).  I am wondering if they ever will.
| 
| Right now I'm not up on the exact details of the outage but if there was a
| hardware problem any messages on disk at the time of the crash may have
| bitten the bullet :( This is conjecture only though.

This seems like a long shot.  In general, a message makes its
way through various hosts until it reaches its destination.  In
this case, the destination host sees that the message is now to
be sent elsewhere and does so immediately.  So, unless the crash
happens in that couple of seconds, the message should not be
lost.

| Those in transit during the outage should be on one of our MXs.  We don't
| necesarily have access to these boxes to check however.  If you haven't
| seen the mail and the sender hasn't got a bounce I'd be confident that its
| out there somewhere.  If a mail item is queued for too long some mail
| servers will "deprioritize" the item and may only attempt delivery ever
| few hours (or even once a day).  I've observed that this tends to be the
| case with larger mail servers (where regular resend attempts is more of a
| problem).

This is all true, of course.  But there's still a puzzle, at
least from where I am.  First, as most people will be aware,
email that is sent to gjb at humbug.org.au now is delivered.  The
delivery is pretty quick, although it was difficult to be sure
of the time from Rob's test message -- his machine's clock seems
to be slow; caliburn's clock is about 3 minutes fast.  However,
my test message made it back here in less than 3 seconds.

But the messages that were sent on Saturday and Sunday have not
been delivered.  The Saturday message got one of those warning
messages from mailer-daemon at mailhub1.uq.edu.au:

<gjb at humbug.org.au>... Deferred: Connection timed out with caliburn.humbug.org.au.
Warning: message still undelivered after 12 hours
Will keep trying until message is 2 weeks old

I've heard nothing about this one since this message at 0348 on
Sunday.  Another message that was sent on Sunday was accepted by
one of the MX hosts and has not yet appeared.  Normally, over
such a time, it would have been re-tried ages ago and caliburn
would have been up and ...

| I knew you'd be up on the mail routing Greg, but I figured others on the
| list would like to know what was happening.

Yes, this might even provide some useful clues about mail
routing and general message handling.  I don't actually care
about the lost messages in this case -- but I do like to know
what happens to email that doesn't get to its intended target.

Greg

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