[Dovecot] outlook2007 shows frequent imap disconnect no matter what outlook-idle setting in dovecot.conf

[Kielbasiewicz, Peter]

Hello,
I saw the problem quite often in various posts but could not find a real solution .
Problem is that I frequently get annoying popups from outlook 2007 about imap idle timeouts which block working with outlook until the popup is acknowledged.

The popup says:
 Your IMAP server closed the connection. This can occur if you leave the connection idle for too long.
 Protocol: IMAP
 Server:     testhost
 Port:         143
 Error Code: 0x800CCCDD

I tried to run dovecot with or without  "imap_client_workarounds = outlook-idle" but do not see any difference.
I am running dovecot on Red Hat Enterprise Linux Client release 5.1 (Tikanga).
Below is the output of some commands to get a clue about my config.

Background info:
Our primary mailboxes are on exchange servers.
As there is a size limit on the server mailboxes I am evaluating a local storage solution for our users.
Thus  I set up an additional mailbox in outlook using IMAP.
Local .pst files can not be backuped easily (especially when outlook is running) and I am investigating a local IMAP server where users can move their mails to. This server can easily be backuped (even incrementally when using Maildir) and users do  always have access to their mails.
The drawbacks are that users must have an extra login to the imap server because I have no ldap access to the company AD server from our local site domain.
The solution will not be accepted though if I can not prevent the frequent disconnect popups.

Peter


#dovecot --version
1.0.rc15

#dovecot -n
# /etc/dovecot.conf
protocols: imap imaps
login_dir: /var/run/dovecot/login
login_executable: /usr/libexec/dovecot/imap-login
mail_location: maildir:~/Maildir
maildir_copy_with_hardlinks: yes
auth default:
  passdb:
    driver: pam
  userdb:
    driver: passwd

# tail /var/log/messages
Mar 26 06:45:28 testhost dovecot: imap-login: Login: user=<peter>, method=PLAIN, rip=::ffff:130.143.81.176, lip=::ffff:130.143.83.92
Mar 26 06:46:01 testhost dovecot: IMAP(peter): Disconnected: Logged out
Mar 26 06:46:01 testhost dovecot: IMAP(peter): Disconnected
Mar 26 07:15:31 testhost dovecot: imap-login: Login: user=<peter>, method=PLAIN, rip=::ffff:130.143.81.176, lip=::ffff:130.143.83.92
Mar 26 07:15:31 testhost dovecot: imap-login: Login: user=<peter>, method=PLAIN, rip=::ffff:130.143.81.176, lip=::ffff:130.143.83.92
Mar 26 07:16:04 testhost dovecot: IMAP(peter): Disconnected
Mar 26 07:16:04 testhost dovecot: IMAP(peter): Disconnected
Mar 26 07:40:13 testhost dovecot: imap-login: Login: user=<peter>, method=PLAIN, rip=::ffff:130.143.81.176, lip=::ffff:130.143.83.92
Mar 26 07:40:13 testhost dovecot: imap-login: Login: user=<peter>, method=PLAIN, rip=::ffff:130.143.81.176, lip=::ffff:130.143.83.92
Mar 26 07:40:39 testhost dovecot: IMAP(peter): Disconnected