Intrusion detection systems: complement to firewall security system

The main purpose with firewall is to protect against unauthorized external attacks but it will normally leave the network unprotected from internal attacks or intrusions. Fire walls and access control have been the most important components used in order to secure network and its resources. They work to prevent attacks from taking place or getting into the internal network. However the attackers seldom get their way into the internal protected network, by bypassing the security systems offirewalls and other access control measures. These security measures do not know what happens inside once they are bypassed. There is, therefore needforanothersystem that - will help detect these threats and possibly remove them. This system, which this paper seeks to explore, is called Intrusion Detection System. This will make the network and its resources more secured.Keywords: Intrusion, Firewall Security, Detection,Access control, network securit