输入通信量流进入交换站（台）所通过的地方。 Point through which the incoming traffic flow enters a switching stage.
在防火墙内部，对于来自内外部路由器的通信量来说，唯一允许到达的目的地是bastion主机。 Inside of the firewall the only permit destination for traffic from the interior or exterior route is the bastion host.
