If your organization connects to the Internet, you should pay attention to your firewalls. NetScreen Technologies' NetScreen 10 firewall provides network address translation, user authentication and dynamic filtering. A firewall, by itself, is not enough to protect a network, any more than even the strongest dead bolt is all that's needed to protect a building from intruders. But a firewall is an essential component of a successful security strategy.
Firewalls come in both hardware and software forms.
Although all firewalls are programmed, some are marketed as software products that can be installed on the hardware platform of your choice. Others are sold as standalone hardware units or as features of hardware routers. This guide includes firewalls of both types. Organizations started developing firewall devices in the early days of the Internet, when routers were set up to filter packets based on source and destination. A firewall box compares the addresses of all inbound and outbound IP packets with lists of addresses.