Intrusion detection system (IDS) is differ from the firewall and the anti- virus software, because it can monitor the dynamic behavior character of the network or the computer system, and take active recovery measure to hold back intru- sion.

• 入侵检测系统作为不同于防火墙和防病毒软件的主动防御的最后一道防线,能够用于监控网络或计算机系统的动态行为特征,并采取主动防御措施来阻止入侵的发生。