METHOD AND DEVICE FOR MONITORING NETWORK

摘要

PROBLEM TO BE SOLVED: To find an illegal connection to a network by asking to a device having a function for getting to know network constitution to observe and record network constitution and extracting the difference between an observing result and a previous observing result to recognize the variation of network constitution. SOLUTION: A network monitoring device 308 has ability of acquiring network constitution and a means for obtaining characteristic information concerning a network device, and has a register list 311 for registering an allowable network device and network constitution. If a camera 301d is connected to the network at this time, the network device on the network and network constitution are varied. A network monitoring device 308 acquires information on the network device and network constitution and compares it with the list 311. When these information and constitution do not agree with the contents of the list 311, the device 308 gives a warning.