This specifies the default base directory or name entry to use for the
 reverse address mapping links to the node name (also called the back
 translation links).

     REVERSE_DIRECTORY rev-dir-name

 The links under this directory are used to map NSAP values to their
 respective node names.  These directories are used only for the DECdns
 directory service.

 For example:

     SET DEFAULT DIRECTORY_SERVICE DECDNS REVERSE_DIR .DNA_BackTranslation

 For more information, please refer to the NAMES_AND_DIRECTORIES topic.