Networks play a central role in cyber-security: networks deliver security attacks, suffer from them, defend against them, and sometimes even cause them. This article is a concise tutorial on the large subject of networks and security, written for all those interested in networking, whether their specialty is security or not. To achieve this goal, we derive our focus and organization from two perspectives. The first perspective is that, although mechanisms for network security are extremely diverse, they are all instances of a few patterns. Consequently, after a pragmatic classification of security attacks, the main sections of the tutorial cover the four patterns for providing network security, of which the familiar three are cryptographic protocols, packet filtering, and dynamic resource allocation. Although cryptographic protocols hide the data contents of packets, they cannot hide packet headers. When users need to hide packet headers from adversaries, which may include the network from which they are receiving service, they must resort to the pattern of compound sessions and overlays. The second perspective comes from the observation that security mechanisms interact in important ways, with each other and with other aspects of networking, so each pattern includes a discussion of its interactions.

中文翻译：

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网络安全中的模式和交互

网络在网络安全中发挥着核心作用：网络提供安全攻击、遭受攻击、防御攻击，有时甚至引发攻击。本文是关于网络和安全这一大主题的简明教程，为所有对网络感兴趣的人编写，无论他们的专长是安全与否。为了实现这一目标，我们从两个角度得出我们的重点和组织。第一个观点是，尽管网络安全机制极其多样化，但它们都是少数模式的实例。因此，在对安全攻击进行了实用分类之后，本教程的主要部分涵盖了提供网络安全的四种模式，其中熟悉的三种模式是加密协议、数据包过滤和动态资源分配。尽管加密协议隐藏了数据包的数据内容，但它们无法隐藏数据包头。当用户需要向对手隐藏数据包标头时，其中可能包括他们从中接收服务的网络，他们必须求助于复合会话和覆盖的模式。第二个观点来自对安全机制以重要方式相互作用的观察，相互之间以及与网络的其他方面，因此每个模式都包含对其相互作用的讨论。