合理实施防火墙配置

今天我们所处的信息时代，也可以说也是病毒与黑客大行其道的时代。这样说也许有些悲观，但今天的网络的确如此。从Internet到企业内网、从个人电脑到可上网的手机平台，没有地方是绝对安全的。每一次网络病毒的攻击，都会让家庭用户、企业用户、800热线甚至是运营商“头痛脑热”。不过，经历过了一次又一次的病毒危机后，人们已经开始思考网络的安全了。     

图说防火墙的使用

相信大家对冲击波和震荡波都不陌生，但并非每个人都亲眼目睹过，也许你的系统升级及时，也许你的运气好。笔者“有幸”经历了局域网内疯狂的“震荡”，并尝试利用防火墙战而胜之，本文配图说明了瑞星个人防火墙2004的相关设置。     

如何更加合理的配置防火墙

今天我们所处的信息时代,也可以说也是病毒与黑客大行其道的时代,这样说确实有些悲观但今天的网络的确如此,从Internet到企业内网、从个人电脑到可上网的手机平台,没有地方是安全的。每一次网络病毒的攻击,都会让家庭用户、企业用户、800热线甚至是运营商头痛脑热。不过经历过了一次又一次的病毒危机后,人们已经开始思考网络的安全了。     

过滤型防火墙的使用

一 防火墙的作用及现状 防火墙是最常见的安全防护产品,本刊2000年的培训栏目曾介绍过防火墙的原理和技术,本期介绍过滤型防火墙的使用。 过滤型防火墙提供的安全性功能主要有:数据过滤功能、状态检测功能、双机热备功能、流量和时间段控制功能、防止地址欺骗功能、透明安全代理功能、     

新旧防火墙的搭配使用

本文就目前社会所关心的网络防火墙升级改造过程中陈旧设备的再利用问题进行了分析并提出了几种解决方案.     

使用Linux构筑复合型防火墙

介绍防火墙软件包IPCHAINS的工作原理,给出建立一套相对完整的高速复合型防火墙的详细步骤。该防火墙可保护防火墙内部各机器的安全,提供一系列正常的服务,并拒绝其它类型数据包的通过。     

天网个人防火墙使用问答

天网防火墙个人版是一套供个人电脑使用的网络安全程序，它可帮你抵挡网络入侵和攻击，防止信息泄露。 天网防火墙个人版把网络分为本地网和互联网，可以针对来自不同网络的信息设置不同的安全方案、以下所述的问题都是针对互联网而言的，故所有的设置都是在互联网安全级别中完成的。 怎样防止信息泄露？ 如果把文件共享向互联网开放，而且又不设定密码，那么别人就可以轻松地通过互联网看到您机器中的文件；如果还允许共享可写，那别人甚至可以删除文件。你可以在天网个人防火墙的互联网安全级别设置中将ＮＥＴＢＩＯＳ关闭（这种设置不会…     

使用Windows防火墙十问答

1.问:我使用不同的Windows版本,怎么办呢?答:WindowsXP前的Windows版本不含内建防火墙。如果计算机用的是旧版Windows,如Win-dows2000、WindowsMillenniumEdition或Windows98,你应取得防火墙,并加以安装。可使用硬件防火墙或软件防火墙。2.问:如果我在家中或小型办公室网络中有     

使用iptables构建Linux防火墙

本文介绍了在Linux防火墙的发展过程、iptables的工作原理以及通过iptables构建防火墙的方法。     

On the use of open-source firewalls in ICS/SCADA systems

ABSTRACT

Firewalls are one of the most widely used security devices to protect a communications network. They help secure it by blocking unwanted traffic from entering or leaving the protected network. Several commercial vendors have extended their firewall capabilities to support SCADA protocols or designed SCADA-specific firewalls. Although open-source firewalls are used successfully in IT networks, their use in SCADA networks has not been properly investigated. In this research we investigate the major open-source firewalls for their use in SCADA networks and identify Linux iptables’ potential as an effective SCADA firewall. Iptables is a powerful open-source firewall solution available as part of most Linux distributions in use today. In general, use of iptables as a network-level firewall for SCADA systems has been limited to basic port and host filtering, without further inspection of control messages. We propose and demonstrate a novel methodology to use iptables as an effective firewall for SCADA systems. This is achieved by utilizing advanced iptables features that allow for dynamic inspection of packet data. It is noteworthy to mention that the proposed solution does not require any modification to the netfilter/iptables framework, making it possible to turn a Linux system into an effective SCADA firewall. The approach has been tested by defining filtering rules for the Modbus TCP protocol and validating its ability to defend against various attacks on the protocol.     

Validating firewalls using flow logics

The ambient calculus is a calculus of computation that allows active processes to communicate and to move between sites. A site is said to be a protective firewall whenever it denies entry to all attackers not possessing the required passwords. We devise a computationally sound test for validating the protectiveness of a proposed firewall and show how to perform the test in polynomial time. The first step is the definition of a flow logic for analysing the flow of control in mobile ambients; it amounts to a syntax-directed specification of the acceptability of a control flow estimate. The second step is to define a hardest attacker and to determine whether or not there exists a control flow estimate that shows the inability of the hardest attacker to enter; if such an estimate exists, then none of the infinitely many attackers can enter unless they contain at least one of the passwords, and consequently the firewall cannot contain any trap doors.     

防火墙的构造与应用

本文作为一篇防火墙知识的普及性文章，从介绍防火墙的基本概念开始，详细讨论了防火墙的主要构件以及系统设计，最后给出了几个防火墙的应用实例。目的是使读者对防火墙的构造与应用有一个初步了解。     

A new perspective on firewalls

No topic seems to have captured the fancy of information security professionals as has the topic of firewalls. Firewalls are commonly defined as security barriers between an internal network and other networks external to that network. The topic of firewalls is not only disproportionately represented in the agenda of information security conferences and workshops but is the focus of a number of net groups (e.g. Firewalls Digest) that generate a prolific number of postings. Indeed, firewalls are receiving so much attention today that it is difficult to imagine anything new that could be said. Corporations offering information security services now routinely advertise ‘state-of-the-art’ consulting in firewall design and evaluation.     

Optimization of parallel firewalls filtering rules

As filtering policies are getting larger and more complex, packet filtering at firewalls needs to keep low delays. New firewall architectures are needed to enforce security and meet the increasing demand for high-speed networks. Two main architectures exist for parallelization, data-parallel and function-parallel firewalls. In the first, packets are distributed across a set of identical firewalls that implement the entire policy. In the second, each firewall implements a subset of the policy with a fewer number of rules, but the packets have to be duplicated and processed by all the firewalls. This paper proposes a new architecture function-parallel with pre-processing that combines the advantages of both architectures. The proposed architecture has the advantage of not duplicating the data, so that the processing time can be significantly reduced. Moreover, our architecture enables stateful inspection of packets, which is necessary to prevent multiple types of attacks. The performances of this architecture have been proven to be scalable for large security policies.

     

代理型防火墙的原理与应用

防火墙主要分为过滤形和代理型两大类,上期介绍了过滤型防火墙的应用,本期介绍代理型防火墙。1 代理型防火墙的工作原埋 代理型防火墙安装在内部网与外部网的隔离点,起着监视和隔绝应用层通信流的作用。同时也常结合出入过滤器的功能。