Network security refers to any activities designed to protect network and related activities. It protects the usability, reliability, integrity, and safety of network and data. Good network security identifies a variety of threats and stops them from entering or spreading on network.

The network security concerns with allowing only legal or authorized users and programs to gain access to information resources like databases. It also ensures that properly authenticated users get access only to those resources that they are supposed to use. 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

A network security system usually consists of many components. Ideally, all components work together, which minimizes maintenance and improves security. Network security components include:

• Anti-virus and anti-spyware.
• Firewall, to block unauthorized access to your network.
• Intrusion prevention systems (IPS), to identify fast-spreading threats, such as zero-day or zero-hour attacks.
• Virtual Private Networks (VPNs), to provide secure remote access.

The network security makes use of a variety of resources like user name, password, encrypted smart cards, biometrics, and firewalls to protect resources.