This option is used in conjunction with the tamper-proof settings file under the server. Configuration options that are in the encrypted settings file, ctsrvr.set, cannot be overridden in the ctsrvr.cfg file. The NULL_STRING keyword lets you define a symbol that represents a null string so that options can be blocked in the settings file without activating them.
With the above entry example in the server settings file, LOCAL_DIRECTORY is blocked from use in the standard ctsrvr.cfg file but it is not activated.
This configuration option can include an environment variable name that will be substituted with its value when the configuration file is read.
Default: Not enabled