Internetwork zone name filtering with selective placebo zone name substitution in a response to a request for zone name information

A zone filtering intelligent node disposed in an internetwork comprised of a plurality of network ranges, said intelligent node comprising:

• a plurality of ports, each in communication with at least one of said network ranges;
• a data routing element in communication with said plurality of ports for receiving a request, from a requesting node associated with said internetwork, for a zone name information response for a specified network address range, for identifying one of said plurality of sorts as a response port, and for directing said zone name information response to said response port;
• a programmable control unit and associated memory, said programmable control unit for controlling said data routing element and for compiling said zone name information response;
• and
• a plurality of zone name information filters, each associated with a respective one of said plurality of ports and selectively applied by said programmable control unit to said zone name information response directed through said respective port by said data routing element,
• wherein each of said zone name information filters is customized for the respective one of said plurality of ports and may be unique among all of said zone name information filters,
• wherein, for each zone name information response, said programmable control unit removes zone names to be filtered from said response according to said zone name information filter associated with said response port, and
• wherein said zone name information response comprises a placebo zone name, inserted into said zone name information response by said programmable control unit, if said zone name information response would otherwise contain only zone names to be filtered based upon said response port-associated zone name information filter.