[Dovecot] dovecot-auth leaves zombies

[Stefano Maffulli]

Hi all,

I have installed and configured dovecot on two different machines, so
I don't have much experience with this server.  One installation is
giving me serious problems, that I have a hard time tracing.  From the
beginning: the machine is a debian mix (stable/unstable) dovecot
0.9.11, real users authenticated via pam_ldap/nss_ldap.  It serves ~70
users, all of them using Outlook, Outlook Express and IMP.

The system seems to work just fine for a while, but after a some time,
some dovecot-auth zombies start appearing.  I can't really understand
who/what is causing them.  The only thing I see in the logs are these
lines, very sporadically, but I still couldn't trace when they
happened.

Nov  5 09:40:28 csv-mail-01 dovecot-auth: nss_ldap: reconnecting to
LDAP server...
Nov  5 09:40:28 csv-mail-01 dovecot-auth: nss_ldap: reconnected to
LDAP server after 1 attempt(s)

(BTW, also apache2 sends similar messages, I don't know if they are related)
Nov  5 09:52:14 csv-mail-01 apache2: nss_ldap: reconnecting to LDAP server...
Nov  5 09:52:14 csv-mail-01 apache2: nss_ldap: reconnected to LDAP
server after 1 attempt(s)

After a while dovecot stops authenticating and needs to be killed and
restarted (/etc/init.d/dovecot stop takes some time to actually stop
dovecot processes).

Do you have any clue of what is going on and where I can investigate
further?  I would like to say 'it's Outlook's fault', but I really
can't.  Any hint appreciated.

regards
stef