A cable modem is a device that enables you to hook up your PC to a local cable TV line and receive data at about 1.5 Mbps.
A next-generation firewall (NGFW) is a part of the third generation of firewall technology that is implemented in either hardware or software and is capable of detecting and blocking sophisticated attacks by enforcing security policies at the application, port and protocol levels.
A proxy firewall is a network security system that protects network resources by filtering messages at the application layer. A proxy firewall may also be called an application firewall or gateway firewall.
A Web application firewall (WAF) is a firewall that monitors, filters or blocks traffic to and from a Web application. WAFs are especially useful to companies that provide products or services over the Internet.