[NTLUG:Discuss] Mail Server Resends Messages

[Jack Snodgrass]

On Thu, 2004-07-15 at 10:52, Stuart Johnston wrote:
> I generally use Mozilla Mail and the UW Mail server for my email so I'm 
> not sure if this is a problem with the client or the server.  Although, 
> I suspect the server.
> 
> Every now and then (generally months apart) Mozilla will redownload all 
> of the messages from the server.  For users with POP set to keep 
> messages on the server this results in duplicates of all messages in 
> their inbox.  For IMAP users (ie, the smart ones ;) Mozilla simply 
> redownloads the headers and everything goes back to normal.
> 
> Has anyone else seen this happen or know how to fix it?
> 
> Thanks,
> Stuart Johnston

First of all... it's not the mail server ( Sendmail/Qmail ) that is 
'resending' the message, but it's your mail client re-downloading 
the email. The POP3/IMAP server never 'sends' mail... your client
requests/retrieves it.... 


FYI:
The POP3 Protocol doesn't/hasn't/won't officially support 'Leave the
mail' on the server. The unofficial way is to exit the POP3 server and
NOT send the 'DELE' command. The 'DELE' command tells the server to
delete the mail from the server. If the 'DELE' command isn't sent, the
server assumes that the client failed so it just resets and doesn't 
delete anything. The Client has to 'remember' the last Message id 
of the email that it did download and the number of messages that 
are on the server. 

Now... if it takes months... it's probably a 'MAX' value on the 
client that resets and when it resets, it gets confused. It 'forgets' 
the last email message and ends up getting them  all. 

I doubt its' the server..... unless... the server 'ages' some 
of the mail that is sitting in the mbox... when that happens, 
the message numbers for the server might not match what the client 
thinks they are... when ever the client gets confused or doesn't 
see the message number on the server it expects, it just downloads
everyting. 

I've used IMAP for several years now... way too many problems
with POP3-leave-the-mail-on-the-server..... also... IMAP 
folders ( Sent mail on the server so you can see yoru Sent Mail 
folder from anywhere... ) or just my ToDo folder that I can access
from home, work, or the airport.... IMAP is the way to go. 

jack