[NTLUG:Discuss] Mail Server Resends Messages

[Stuart Johnston]

Jack Snodgrass wrote:
> 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.... 
> 

Yeah, poorly written subject.  Sorry.

> 
> 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 should have mentioned before, the main reason I doubt it is the client 
is that it happens at the same time to multiple people using different 
machines which were all configured at different times.

> 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 suspect it is something like that.  I just haven't been able to find 
any more specific details.

> 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. 

I know.  Some of my co-workers are just too stubborn to switch.  I 
suppose that if they'd rather sit and delete all the duplicate messages 
instead of using IMAP then they will just have to live with it.


Stuart Johnston