While trying to create calendar events in roundcube mailbox interface postfix generates multiple LDAP timed out warnings and failed to deliver mails with events. Sometimes it's happening while trying to deliver usual messages. Here are the steps to reproduce this behaviour.
- Install latest Kolab 16 following https://docs.kolab.org/installation-guide/centos-7.html and https://docs.kolab.org/installation-guide/setup-kolab.html#installation-guide-setup-kolab guides on the latest CentOS 7 release.
- Create POSIX mail-enabled user on kolab webadmin interface
- Login to webmail and create new event in calendar with external participants (e.g. gmail.com or hotmail.com) and message reminder
After that some events can not be sent with the following warning|error messages in /var/log/maillog:
... Sep 22 22:03:32 kolab postfix/trivial-rewrite[2749]: warning: dict_ldap_connect: Unable to bind to server ldap://localhost:389 with dn uid=kolab-service,ou=Special Users,dc=XXXXXXXX,dc=com: -5 (Timed out) Sep 22 22:03:32 kolab postfix/trivial-rewrite[2749]: warning: ldap:/etc/postfix/ldap/mydestination.cf: table lookup problem Sep 22 22:03:42 kolab postfix/trivial-rewrite[2749]: warning: dict_ldap_connect: Unable to bind to server ldap://localhost:389 with dn uid=kolab-service,ou=Special Users,dc=XXXXXXXX,dc=com: -5 (Timed out) Sep 22 22:03:42 kolab postfix/trivial-rewrite[2749]: warning: ldap:/etc/postfix/ldap/mydestination.cf: table lookup problem Sep 22 22:03:52 kolab postfix/trivial-rewrite[2749]: warning: dict_ldap_connect: Unable to bind to server ldap://localhost:389 with dn uid=kolab-service,ou=Special Users,dc=XXXXXXXX,dc=com: -5 (Timed out) Sep 22 22:03:52 kolab postfix/trivial-rewrite[2749]: warning: ldap:/etc/postfix/ldap/mydestination.cf: table lookup problem ...
Sometimes LDAP server is blocked continously for more than 10 minutes and servvices can't bind or search in LDAP at this time.
I tried different VMs with local and external IP-addresses and all had the same problem even after clean install and configuration.
CentOS and Kolab versions:
# rpm -qv pykolab pykolab-0.8.3-3.3.el7.kolab_16.noarch # cat /etc/centos-release CentOS Linux release 7.2.1511 (Core)