A hardware firewall sits between your local network of computers and the Internet. The firewall will inspect all the data that comes in from the Internet, passing along the safe data packets while blocking the potentially dangerous packets. In order to properly protect a network without hindering performance, hardware firewalls require expert setup, and so may not be a feasible solution for companies without a dedicated IT department. For businesses with many computers, however, being able to control network security from one single device simplifies the job.