I just had an interesting experience. Installed the January 2015 Scheduled Maintenance patch to OES11 SP2 and rebooted. The server came back up but seemed like LDAP wasn't working.
novell-dhcpd failed to start with error message indicating that it can't find the DHCP_server object, also I couldn't log in to iManager because "the user was not found in specified context". At the same time, netstat showed that ports 389 and 636 were up.
Lacking any better ideas , I performed a rcndsd restart which magically fixed things. I didn't have time for immediate troubleshooting at the moment, but now that I'm looking at /var/log/messages and /var/opt/novell/eDirectory/log/ndsd.log, I can't find any error messages other than those that are always there. Is there some other log file where LDAP-related error messages could be found (other than tracing with ndstrace, for which the chance has passed)?