Pakemon has been developped to share IDS components based on the open source development model. The current version of pakemon monitors all traffic on a network, reconstruct ip packets and tcp segment, search given data patterns(regular expression) in the traffic and issue alerts if necessary, log to a file or send a message to syslog. This software is for experimental. Please use this at your own risk. There are still many things to improve. If you have any suggestion, question, idea or comments please feel free to contact the author, keiji@sfc.keio.ac.jp or to the mailing list pakemon-devel@inas.mag.keio.ac.jp.