Definition

A security appliance is a low-cost computer system designed  to provide specialized security functions, such as a network firewall or e-mail  security. The appliance is a hardware component that includes all the required software, including a proprietary operating  system. Like household appliances, security appliances usually cannot be  repaired or upgraded by the administrator, and they are usually “plug and  play,” meaning they simply need to be plugged into the network to work.

Business applications

Security appliances offer specialized security functions in  a single, pre-configured, easy-to-manage and -deploy form factor. Organizations  can deploy these “point solutions” to enforce policies, detect network  intrusions, create and manage virtual private networks, manage e-mail security, and more.

Deployment Concerns

Security appliances are intended to simplify security, but some appliances have evolved to such an extent that they provide a simple way to manage complexity. This is the case with appliances for application integration, which  is inherently complex.

Organizations increasingly rely on appliances of all types, resulting in “appliance overload.” As organizations deploy more and more appliances to perform security and other functions, the ease-of-use and management benefits are replaced by complexity and the cost of managing multiple single-point solutions.