[Dovecot] "ldap_result() failed: Can't contact LDAP server" log messages

[Mike Brudenell]

Greetings -

I', continuing to build a test system that, at present, only I have  
access to.  It is running Dovecot 1.0rc24.  Here's the output of a  
"dovecot-n"...

# /usr/local/etc/dovecot.conf
log_path: /logfiles/mail/live/dovecot
protocols: imap
ssl_cert_file: /usr/local/etc/ssl/certs/imapservice-bundle.crt
ssl_key_file: /usr/local/etc/ssl/private/imapservice-private.key
disable_plaintext_auth: no
login_dir: /var/run/dovecot/login
login_executable: /usr/local/libexec/dovecot/imap-login
login_process_per_connection: no
login_greeting_capability: yes
mail_location: maildir:/mailstore/%1u/%u/Maildir:INDEX=/var/dovecot/ 
index/%1u/%u:CONTROL=/var/dovecot/control/%1u/%u
mail_debug: yes
mmap_disable: yes
maildir_copy_with_hardlinks: yes
mail_log_prefix: %Us(%u)[%p]:
imap_client_workarounds: delay-newmail outlook-idle
namespace:
   type: private
   separator: /
   inbox: yes
auth default:
   mechanisms: plain login
   cache_size: 1024
   cache_ttl: 600
   username_chars:  
abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890
   username_format: %Lu
   passdb:
     driver: ldap
     args: /usr/local/etc/dovecot-ldap-passdb.conf
   userdb:
     driver: ldap
     args: /usr/local/etc/dovecot-ldap-userdb.conf

We are using LDAP for the passdb and userdb.

The oddity is that even on a quiescent system (Dovecot started from  
scratch, but no connections being made to it) we are seeing these  
messages being logged, apparently every 5 minutes:

dovecot: Mar 09 11:09:44 Error: auth(default): LDAP: ldap_result()  
failed: Can't contact LDAP server
dovecot: Mar 09 11:09:44 Error: auth(default): LDAP: ldap_result()  
failed: Can't contact LDAP server
dovecot: Mar 09 11:14:45 Error: auth(default): LDAP: ldap_result()  
failed: Can't contact LDAP server
dovecot: Mar 09 11:14:45 Error: auth(default): LDAP: ldap_result()  
failed: Can't contact LDAP server
dovecot: Mar 09 11:19:45 Error: auth(default): LDAP: ldap_result()  
failed: Can't contact LDAP server
dovecot: Mar 09 11:19:45 Error: auth(default): LDAP: ldap_result()  
failed: Can't contact LDAP server

I'm guessing there are two log entries each time because of separate  
connections being used for the passdb and userdb.

The LDAP server *is* available throughout.

I'm wondering if Dovecot is trying to hold the connection open but,  
after a timeout of 5 minutes of inactivity, the LDAP server is  
closing it and causing Dovecot to log this message.

If this is indeed the case then I guess on a production server these  
message will be rarely if ever seen.

Obviously I'd prefer not to have such worrying-sounding log entries  
appearing.  (And if my guess is right then they're slightly  
misleading: the LDAP server *can* be contacted!)

Any thoughts?

Cheers,
Mike B-)

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