Raffaele Viola writes:
how can I activate the openldap logs and where I can see the logs?
Tell slapd to log to syslog with e.g. "loglevel 256" in slapd.conf, see man 'slapd.conf'. Restart slapd.
Tell syslog to output the slapd logs: How this is done varies, but typically you append something like local4.* /var/log/openldap.log to /etc/syslog.conf, and kill -HUP <the syslog pid> to tell syslogd to re-read the config file. (slapd uses the local4 syslog level by default.)
On some systems you can put '-' in front of the filename to tell syslogd to write log lines in batches instead of one by one. This can remove a significant I/O bottleneck if you have a lot of traffic. See man syslogd or man syslog.conf.