Problem
You notice entries like this in your logfiles:
Nov 5 15:07:13 ucs slapd[1257]: connection_read(241): no connection!
Solution
These messages indicate a lost connection from a client (ie searching ldap database) not a failure on the server side.
They can safely be ignored in case you will not troubleshoot or fix your client.
You might use LDAP debug to display further information or reduce loglevel to hide these messages
root@master:/# ucr search ldap/debug
ldap/debug/level: none
This variable configues the verbosity of the log messages of the LDAP server. A description of the possible options can be found in 'man slapd.conf' under 'loglevel'.