[Dovecot] Dovecot and loadbalancer

Hi all,

I've 4 servers with dovecot and ldap authentication behind a
loadbalancer (Alteon).

To connect to dovecot, client need to use a vip of the loadbalancer.

To connect to the ldap server, dovecot need to use the loadbalancer
cause there are several ldap server.

The loadbalancer close a connection without activity during 30mn

Dovecot lauch several authentication process who have a connection to
the ldap server each.

Each client (user) have several imap connection to dovecot.

I've 2 problemes :

• If a client (thunderbird for ex.) don't use a connection during
  30mn, the loadbalancer delete this connection from his connection
  table and the client seem not able to correctly reopen another

• If a dovecot authentication proccess want to request ldap but
  haven't do it in the last 30mn, it fail an say that the
  authentification fail.

Somebody have already use dovecot in a redundent environnement ?

Have you an idea to solve these problems

Thanks,

Cyril Feraudet