由于网络庞大的覆盖面、繁杂的多能性使得其与计算机系统的基本安全原则——“最少即是最安全的”相违背,所以网络的脆弱性也随之相对明显。可以说从有网络的那_天开始,网络上的安全问题就从没有间断过。针对来自网络的威胁,我们通常是采取以下方法进行防御的。 Due to the huge network coverage and the complicated pluripotency that make it contrary to the basic security principle of computer system - “least is the safest”, the vulnerability of the network is relatively obvious. It can be said that there is a network that day, the network security problems never stopped. We usually take the following measures to defend against the threat from the Internet.