Basically, a firewall is a stand-alone process or a set of integrated processes that runs on a router or server to control the flow of networked application traffic passing through it.

• 防火墙基本上是一个独立的进程或一组紧密结合的进程，运行于路由器或服务器，来控制经过防火墙的网络应用程序的通信流量。