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 hardware- or software-based network security system that is able to detect and block sophisticated attacks by enforcing security policies at the application level, as well as at the port and protocol level.
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.