Network security refers to any activities designed to protect your network. Specifically, these activities protect the usability, reliability, integrity, and safety of your network and data. Effective network security targets a variety of threats and stops them from entering or spreading on your network. Many network security threats today are spread over the Internet. The most common include: Viruses, worms, and Trojan horses Spyware and adware Zero-day attacks, also called zero-hour attacks Hacker attacks Denial of service attacks Data interception and theft Identity theft Network security is accomplished through hardware and software. The software must be constantly updated and managed to protect you from emerging threats.