Server Security: Keeping Your Data Safe Page 3
By Karl Magsig
Where it is not possible to run a dedicated gateway server, a firewall is required. There are two basic options available; a hardware firewall or a software firewall. A hardware firewall is physical equipment that stands between the local network and the Internet, and blocks all incoming or outgoing connections unless it is specifically configured to allow them. Vendors that offer good firewall hardware are BorderWare, found at http://www.borderware.com and Cisco, http://www.cisco.com/warp/public/cc/pd/fw/sqfw500/.
Hardware firewalls are perhaps the most secure firewall solution since they are dedicated to the task of protecting the network. If a hacker were able to actually connect to the corporate firewall device, there would be no important data stored there, and thus they probably would not be able to do much irreversible damage.