These two parameters are in (or can be added to) the server's LDAP configuration file (/library/preferences/directoryservice/DSLDAPv3PlugInConfig.plist).
Delay Rebind
The parameter takes this form:
<key>Delay Rebind Try in seconds<\\key>
<integer>n<\\integer>
This parameter should be located near "<key>OpenClose Timeout in seconds<\\key>".
The value "n" specifies how long the LDAP plugin waits before trying to reconnect to a server that fails to respond. You can increase this value to prevent continuous reconnection attempts.
Idle Timeout
The parameter takes this form:
<key>Idle Timeout in minutes<\\key>
<integer>n<\\integer>
If this parameter is not already in the file, add it near "<key>OpenClose Timeout in seconds<\\key>".
This setting specifies how long the LDAP plugin will sit idle before disconnecting from the server. You can adjust this value to reduce overloading the server's connections from remote clients.
Related document
If you need help modifying a configuration file, see technical document 106619, "
Mac OS X Server: How to Locate and Edit Configuration Files".