Host intrusion detection systems (HIDS) and network intrusion detection systems (NIDS) are methods of security management for computers and networks. In HIDS, anti-threat applications such as firewalls, antivirus software and spyware-detection programs are installed on every network computer that has two-way access to the outside environment such as the Internet. In NIDS, anti-threat software is installed only at specific points such as servers that interface between the outside environment and the network segment to be protected.
All methods of intrusion detection (ID) involve the gathering and analysis of information from various areas within a computer or network to identify possible threats posed by hackers and crackers inside or outside the organization. Host-based and network-based ID systems have their respective advantages and limitations. The most effective protection for a proprietary network is provided by a combination of both technologies.