Firewalls are one of the best ways to protect your system from attack by users on the Internet. You can use a firewall to separate your internal network from the Internet. A firewall restricts inbound and outbound access, and it can analyze all traffic between your network and the Internet. A firewall can range from a simple packet filter to complex bastion hosts that analyze traffic for each application type. A bastion host is any computer that must be secure because it is accessible from the Internet and exposed to attack. A firewall can be a single router or computer, or it can be a combination of components such as routers, computers, networks, and software.
There are several types of firewall software and hardware you can use to protect your organization from outside attacks, including: