Today that usually means installing a firewall. A firewall controls the content of inbound and outbound network traffic, allowing only authorized traffic through its filters. A firewall typically sits at the point where an agency's private network meets the public Internet, but multiple firewalls placed strategically throughout the network are often recommended today. Just installing the firewall is not enough. Administrators must take the time to configure and administer firewalls.
Firewall problems tend to arise when certain network services are exempt from firewall controls.
For example, some or- ganizations have set up Web servers inside their firewalls. Hackers can get access to the Web server and use it as a jumping-off point for their attacks. Not all firewalls are the same. Some provide stronger security, with correspondingly bigger price tags. These are relatively new products whose sole purpose is to detect hacking attempts.