As a unique NBT monitor tool in the world, NBT Host Monitor is quite powerful and has graphic user interfaces . It could monitor thousands of windows machines simultaneously and scan host name , group name , user name , MAC address of machines in all IP segments in several seconds . It could learn the vendor of the network interface card, and learn the changes made by these machines to host name,group name,user name and MAC address in several seconds, and the startup and shutdown time of machines .NBT Host Monitor could notify administrator these messages in different ways : sending mails , popuping dialogue boxes , sending messages to windows messenger , music (mp3 files ,and related recording work), executing programs , sending syslog messages to syslog servers, it could also record log files .Each item has 3 different states :alive, shutdown, unknown(displayed by different icons ),and would notify administrator when "alive" and "shutdown" states change.NBT Host Monitor owns following advantages : (1) A tool which provides parallel watching , NBT Host Monitor's parallel detecting method is much sensitive , while traditional in-turns method sometimes results in longinterval-time when there are too many IP devices to be watched such as "nbtstat". (2) Rich dealing means such as music, box warnings , network messenger, syslog, mails to as many as 256administrators, running related program , (the program can be developed by administrators , which provides flexibility ) (3) Macro parameters .When popup dialogbox or running related program , the content/title of mails could both be set by administrators ,and the content could contain macro,which can be replaced by other content in real situation .