What is a Firewall?

A firewall is a system or group of systems that are designed to prevent unauthorised access to or from a private network.

Firewalls can be hardware, software, or a combination of both.

Hardware firewalls are typically standalone devices that sit between the public Internet and a company's internal network. Software firewalls are typically part of an operating system or a separate application.

Firewalls use a variety of methods to filter traffic. The most common method is to inspect the source and destination IP addresses of packets to determine whether they should be allowed through.

Other methods include inspecting the packet payload for certain characteristics, such as the presence of a certain string of characters, or verifying the digital signature of a packet.

Firewalls can also be used to block certain types of traffic, such as port scans or packets with certain types of headers.

Firewalls are an important part of network security and are essential for companies that want to protect their internal networks from attack.

Firewalls are also used to protect individual computers from attack. In addition to a software firewall, you can also use a hardware firewall, such as a router with firewall capabilities, to protect your computer.