防火墙

Note that changing the rules in the set or add new rules to re-open the firewall to enable up-to-date entry into force of the firewall rules.

注意，在改变规则设置或添加了新规则后要重新开启防火墙，以使最新的防火墙规则生效。

Network security techniques include router filter, firewalls, intrusion detection, audit, counteroffensive and etc. In these techniques, router filter and firewalls are static security techniques, and others are dynamic security techniques.

目前网络安全技术包括路由器过滤、防火墙、漏洞防堵、入侵检测、审计和反攻击等，其中路由器过滤、防火墙、漏洞防堵属于静态安全技术，而入侵检测、审计和反攻击等属于动态防护。

In this paper, the concept of network security and security structures of OSI and Internet is introduced, and various threats confronting the computer network are also discussed. Several kinds of network information security technologies, including firewall technology, virtual private network, intrusion detection system, data encryption technology, identity authentication and security protocol etc. are also examined. The security of internal network is the biggest problem in the construction of each network. The solution to this problem lies in setting up a firewall. The theory of a firewall and the approach to its actualization is studied. Intrusion detection system, an important part of the computer network security system, has gained extensive attention. IDS monitors the computer and network traffic for intrusion and suspicious activities. It not only detects the intrusion from the extranet hacker, but also the intranet users. The emergence of virtual private network paves the way for realizing secure connection of LAN quickly and at a relatively low cost. The concept, function, key techniques, including the tunnel technology, and the ways to realize VPN are expounded in this paper. Also introduced is the data encrypt network technology, which is called the soul of computer network security, such as digital digest, digital signature, digital certificate, digital encrypt arithmetic and so on. At the same time, the principle and the process of implementing network security by digital certificate and digital signature, the basic principle and characters of security protocols, and finally, three of the security protocols, concerning the security problems in network, IPsec, SLL and SET are analyzed in detail Computer network system should be a system of dynamic defence, both dynamic and static, passive as well as active, and even offensive, combined with management and technology.

本文系统地介绍了网络安全的概念、OSI及Internet的安全体系结构，并讨论了计算机网络面临的各种安全威胁；内部网络的安全问题是每个建网单位面临的最大问题，可以认为防火墙技术是解决网络安全的一个主要手段，本文研究了防火墙的原理及其实现手段；作为一种主动的防御措施，入侵检测系统作为网络系统安全的重要组成部分，得到了广泛的重视，TDS对计算机和网络资源上的恶意使用行为进行识别和响应，不仅检测来自外部的入侵行为，也监督内部用户的未授权活动；虚拟专用网技术的出现，为实现网络间的连接提供了快速安全但又相对便宜的手段，本文较深入的探讨了实现VPN的隧道技术，并对VPN的概念、功能、实现途径、基本构成、关键技术及发展前景等问题进行了全面论述；数据加密技术是网络安全核心技术之一，本文从数据加密算法、数字摘要、数字签名及数字证书等几方面简要介绍了数据加密技术，并分析用数字证书和数字签名实现网络安全的原理和过程；对安全协议的基本原理、主要特点进行了较为深入的研究，并就网络的安全性问题剖析了三种安全协议：IPsec协议、SLL协议和SET协议。

The meaning, category of the fire wall and the advantage of the fire wall and shortage.

防火墙的含义、种类及防火墙的优点与不足。

The functions of fireproofing wall are expounded and its important effect in campus network is discussed.

对防火墙系统的功能进行了较全面的阐述，从而论证了防火墙系统在园区网络中的重要作用。

There are equipments such as fireproofing, VDefend, detecting system, etc.

具体的设备如防火墙、病毒防火墙、入侵检测系统等等。

Use a Firewall - I can not stress how important it is that you use a Firewall on your computer.

使用防火墙-我不能强调有多么重要的是你使用防火墙在您的计算机上。

On the basis of the light-weight system firewall of Linux kernel, this system disposes and transmits the gateway, and start the module of firewall, be used to filter the network data transmitted by the gateway, to stop the data come from illegal address and with forbidden character of packets.

本系统是基于Linux内核的轻型防火墙系统，通过配置转发网关，并启动防火墙模块，对网关转发的数据包进行过滤，对来自非法地址和含有非法字符串的数据包进行拦截。

Following on the official Tencent QQ2007 Ⅱ for example, now almost all of the computer to install antivirus software and firewall security software, firewall, the main role is to prevent illegal access and network attacks, security of our network security.

下面就以腾讯官方的QQ2007Ⅱ为例，现在的电脑中基本上都安装杀毒软件与防火墙等安全软件，防火墙作用主要是阻止非法访问与网络攻击，保障我们的网络安全。

Aside from that, despite the security policy of firewalls are made unifiedly, these policies are usually described in natural language and for the language obscurity, different administrators would have varied understandings, which will lead to inconsistent, configurations between independent firewall policies.

另外，尽管防火墙的安全策略是统一制定的，但是这种安全策略一般由自然语言表示，由于自然语言的模糊性，不同的安全管理员对策略的理解可能并非完全相同，当他们配置独立防火墙的时候也就导致了独立防火墙间的策略不一致。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。