Question 1

Network-based IDS systems (NIDS) are often standalone hardware appliances that include network intrusion detection capabilities. It will usually consist of hardware sensors located at various points along the network or software that is installed to system computers connected to your network, which analyzes data packets entering and leaving the network.

Sensors can be deployed in one of two modes :

a)Inline. An inline sensor is deployed so that the network traffic it is monitoring must pass through it, much like the traffic flow associated with a firewall. One way to achieve an inline sensor is to combine NIDS sensor logic with another network device, such as a firewall or a LAN switch while others are simply IDPSs. The primary motivation for deploying IDPS sensors inline is to enable them to stop attacks by blocking network traffic . Inline sensors are typically placed where network firewalls and other network security devices would be placed