http://nwcom.info/Soft/Ethernet/Network%20Calculator%203.2.1.0/ip%20subnet%20calculator.exe
http://nwcom.info/Soft/Ethernet/Network%20Calculator%203.2.1.0/Network%20Calculator%20Help.cnt
http://nwcom.info/Soft/Ethernet/Network%20Calculator%203.2.1.0/Network%20Calculator%20Help.hlp