Smart Computing Article - Friendly Firewalls: No Trespassing Allowed

offer protection against hackers and crackers. They typically consist of an integrated suite of security components erected as a barrier between a corporate network or a Transmission Control Protocol/Internet Protocol (TCP/IP)-based Intranet designed to serve users within a single enterprise, and an unsecured network, such as the Internet. Since firewalls often cost thousands of dollars and frequently require a separate computer to maintain, they are not the electronic roadblock of choice if you connect to the Internet through a standalone computer. While security for a standalone computer is still a concern, it's a matter of scale. You wouldn't install a firewall to safeguard a single system, just as you probably wouldn't drive to work in a military tank. Since hackers typically target large corporate networks, firewalls are best reserved for interconnected, multi-computer systems. Firewall technology can be as simple as a set of rules designed to filter requests, or as elaborate as a specially configured, multi-computer gateway. In theory, both types of firewalls operate the same way. They function as portals through which all traffic must flow. Firewalls screen and filter any transmission to and from the public network. They shield protected areas on the inside to minimize (if not eliminate) the possibility of data theft, damage, or unauthorized communication. They also log all activity, recording the date and time of any information requests or actions taken. Only authorized traffic has permission to pass through a firewall-protected system. For example, if your corporate Intranet is hooked up to the Internet, you probably don't want intruders rummaging through payroll records, personnel files, or client data bases. You also don't want people on the inside to sabotage the system. All it takes is one disaffected employee to hijack financial data and change the information used in processing payroll. So you configure the firewall