[Dovecot] Deleted / read mails show up as new on remote imap clients

[Ben Morrow]

At  3PM +0100 on 25/02/13 you (Andre Bischof) wrote:
> Am 24.02.2013 19:23, schrieb Daniel Parthey:
> > Hi Andre,
> >
> > Andre Bischof wrote:
> >> Mails, which I already read or deleted via my IMAP client
> >> (Thunderbird) on the same machine running the server (it runs behind
> >> DynDNS on my local machine, thanks to
> >> http://mein.homelinux.com/wiki/mailserver/) show up again if I
> >> connect via IMAP from other client computers, i.e. my notebook
> >> (Thunderbird again).
> > I had a similar problem where deleted folders showed up again
> > in Thunderbird. The following imap_client_workaround setting
> > worked for me:
> >
> > protocol imap {
> >    imap_client_workarounds = delay-newmail tb-extra-mailbox-sep
> > }
[...]
> 
> This is only true for my notebook. On the machine running the server, 
> all subfolders are visible in TB. I have TB configured to move deleted 
> mails to the trash folder - I guess that's default. There is a setting 
> to expunge the inbox when leaving TB - this is unchecked. Could that be 
> connected to the problem? But still, why are my read mails marked unseen 
> when looking them up from my notebook?
> 
> Strange. Any further clues?

Can you use tcpdump or wireshark to see what TB is actually telling the
server to do? If you use TLS you will need to put

    ssl_cipher_list = RSA

in your dovecot.conf and point wireshark at the key file for the
server's certificate; make sure you remove that setting afterwards,
since it's a little less secure. (Specifically, TLS will normally use an
ephemeral Diffie-Hellman key in addition to the certificate's private
key, in order to make as little use of the cert key as possible. This
makes it impossible for a third party (like wireshark) to decrypt the
conversation, even with access to the private key. ssl_cipher_list=RSA
disables this.)

Ben