Basically, a (71) is a standalone process or a set of integrated processes that runs on a router or server to control the flow of (72) application traffic (73) through it. Typically, firewalls are (74) on the entry point to a public network such as the Internet. They could be considered traffic cops. The firewall’ s (75) is to ensure that all communication between an organization’s network and the Internet conform to the organization’s security policies.

75（）

A．male

B．pole

C．role

D．rule

在基本几何三视图中，几何体、机件向基本投影面（）所得的视图称基本视图。

A、画长方形

B、画曲线

C、画圆

D、投影