[Dovecot] Kmail client desconnection

[Jordi Espasa Clofent]

Hi all,

I have a Postfix+Dovecot working in beta/testing; it seems to run very 
fine, but one beta-tester user says that kmail informs him about 
frequent desconnections.

My dovecot -a shows:

# /etc/dovecot.conf
base_dir: /var/run/dovecot
log_path:
info_log_path:
log_timestamp: %b %d %H:%M:%S
syslog_facility: mail
protocols: imaps
listen: [::]
ssl_listen:
ssl_disable: no
ssl_ca_file:
ssl_cert_file: /etc/pki/dovecot/certs/dovecot.pem
ssl_key_file: /etc/pki/dovecot/private/dovecot.pem
ssl_key_password:
ssl_parameters_regenerate: 168
ssl_cipher_list:
ssl_verify_client_cert: no
disable_plaintext_auth: no
verbose_ssl: no
shutdown_clients: yes
nfs_check: yes
version_ignore: no
login_dir: /var/run/dovecot/login
login_executable: /usr/libexec/dovecot/imap-login
login_user: dovecot
login_greeting: Dovecot ready.
login_log_format_elements: user=<%u> method=%m rip=%r lip=%l %c
login_log_format: %$: %s
login_process_per_connection: yes
login_chroot: yes
login_greeting_capability: no
login_process_size: 32
login_processes_count: 3
login_max_processes_count: 128
login_max_connections: 256
valid_chroot_dirs:
mail_chroot:
max_mail_processes: 1024
verbose_proctitle: no
first_valid_uid: 4444
last_valid_uid: 4444
first_valid_gid: 1
last_valid_gid: 0
mail_extra_groups:
default_mail_env:
mail_location: maildir:/var/vmail/%u
mail_cache_fields: flags
mail_never_cache_fields: imap.envelope
mail_cache_min_mail_count: 0
mailbox_idle_check_interval: 30
mail_debug: no
mail_full_filesystem_access: no
mail_max_keyword_length: 50
mail_save_crlf: no
mail_read_mmaped: no
mmap_disable: no
mmap_no_write: no
lock_method: fcntl
maildir_stat_dirs: no
maildir_copy_with_hardlinks: yes
mbox_read_locks: fcntl
mbox_write_locks: fcntl
mbox_lock_timeout: 300
mbox_dotlock_change_timeout: 120
mbox_min_index_size: 0
mbox_dirty_syncs: yes
mbox_very_dirty_syncs: no
mbox_lazy_writes: yes
dbox_rotate_size: 2048
dbox_rotate_min_size: 16
dbox_rotate_days: 1
umask: 63
mail_drop_priv_before_exec: no
mail_executable: /usr/libexec/dovecot/imap
mail_process_size: 256
mail_plugins:
mail_plugin_dir: /usr/lib64/dovecot/imap
mail_log_prefix: %Us(%u):
imap_max_line_length: 65536
imap_capability:
imap_client_workarounds: outlook-idle
pop3_no_flag_updates: no
pop3_enable_last: no
pop3_reuse_xuidl: no
pop3_lock_session: no
pop3_uidl_format: %08Xu%08Xv
pop3_client_workarounds:
pop3_logout_format: top=%t/%p, retr=%r/%b, del=%d/%m, size=%s
auth default:
   mechanisms: plain
   realms:
   default_realm:
   cache_size: 0
   cache_ttl: 3600
   executable: /usr/libexec/dovecot/dovecot-auth
   user: nobody
   chroot:
   username_chars: 
abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@
   username_translation:
   username_format:
   master_user_separator:
   anonymous_username: anonymous
   krb5_keytab:
   verbose: no
   debug: no
   debug_passwords: no
   ssl_require_client_cert: no
   ssl_username_from_cert: no
   count: 1
   worker_max_count: 30
   process_size: 256
   passdb:
     driver: sql
     args: /etc/dovecot_mysql.conf
     deny: no
     pass: no
     master: no
   userdb:
     driver: sql
     args: /etc/dovecot_mysql.conf
   userdb:
     driver: prefetch
     args:
   socket:
     type: listen
     client:
       path: /var/spool/postfix/private/auth
       mode: 432
       user: postfix
       group: postfix
     master:
       path: /var/run/dovecot/auth-master
       mode: 432
       user: vmail
       group: vmail

¿How can I debbug this behaviour or how can I determine if this issue is 
a client or dovecot fail?

TIA.