POP3 re-downloading mail

[Gene Rackow]

It could still be the server at fault (sorta) if the new server has different
timing than the old which is resulting in client side errors which
in turn result in re-download.

I've seen various timing issues, etc that have caused disconnect
problems as well.  This really bit us once in the past where someone
posted something huge to about 20 users.    These users ran into
trouble with the data not transfering in time or the data being too large
to transfer properly over their VPN connections.  That took some tracing
to find out why.  Increasing the server timeouts and updating some older
VPN software fixed the problem, but those users ran into the redownload
the world problem rather badly.


"Michael Nguyen" made the following keystrokes:
 >----- Original Message ----- 
 >From: "Gene Rackow" <rackow at mcs.anl.gov>
 >
 >
 >> I've run into this with a number of pop based clients.  From what I have
 >> seen, the problem comes up on a client IF there was some sort of error
 >> that occured the previous time that client ran.  For example, the
 >> client for some reason disconnected in the middle of downloading a
 >message.
 >> There are 100 message on server.  The last 10 were not seen by the client
 >> yet so it was downloading those.  In the middle of message "new-9" or 99,
 >> an error occurred.  The client now gets confused about what it has and
 >> the next time it downloads, it starts over at message 1.  It's wrong,
 >> but it happens.  I would not blame the server unless I had a strong
 >> case that it really did recalc all message UIDL.
 >
 >This is true.  The most common cause of this is a client error (e.g. a user
 >reinstalls Outlook Express thus removing the list of UIDs).  However,
 >Warrick's issue was that quite a few users were re-downloading email.  I
 >don't know how many users this really is, but if he's talking dozens of
 >users, it's far more likely that it had to do with the new server than
 >anything else.
 >
 >[snip]
 >
 >
 >Michael
 >
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