A network firewall is a security system that is meant to manage access to a computer network. It does this by filtering incoming and outgoing network traffic on the basis of a set of rules that have been specified. In addition to preventing harmful traffic from entering or exiting the network, the primary function of a firewall is to safeguard the network from unauthorized access.
It is possible to create a firewall using either hardware or software, and it is also possible to set the firewall such that it operates at one of many layers of the network stack, including the application layer, the transport layer, or the network layer. They may also be configured to allow or block communication depending on different criteria, such as the IP address of the source or destination, the port number, the protocol, and other properties. This can be done by configuring them to allow or block traffic.
It is common practice to use firewalls in conjunction with other security measures, such as intrusion detection and prevention systems, virtual private networks (VPNs), and antivirus software. Firewalls are an essential element of any network security strategy because of their ability to block unauthorized access to a network.