The LDAP Tool Box project provides a set of LDAP-related applications, administrative tools, and other utilities. They have just released the version 0.7 of their Nagios Plugins component, which can be used to track the health of LDAP servers in the Nagios monitoring system, some of which apply to any type of server, while others are implementation-specific. This release appears to fix a few bugs found in their previous 0.6 release.