Network Firewall Technologies

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科技英语词汇

科技英语词汇

科技英语词汇科技在现代社会中起着至关重要的作用,我们可以通过学习科技英语词汇来更好地理解和应用相关的科技知识。

本文将介绍一些常用的科技英语词汇,并分为四个部分进行分类讨论。

一、计算机与互联网技术(Computing and Internet Technologies)1. Algorithm(算法)- A step-by-step procedure for solving a problem.2. Artificial intelligence(人工智能)- The simulation of intelligent behavior in computers.3. Database(数据库)- An organized collection of data stored and accessed electronically.4. Encryption(加密)- The process of converting information intoa secret code to prevent unauthorized access.5. Firewall(防火墙)- A network security system that monitors and controls incoming and outgoing network traffic.6. HTML(超文本标记语言)- The standard language for creating web pages and web applications.7. Network(网络)- A group of interconnected devices that can share resources and communicate with each other.8. Operating system(操作系统)- The software that manages computer hardware and software resources and provides common services for computer programs.9. Software(软件)- The programs and operating information used by a computer.10. Virus(病毒)- A type of malicious software that can replicate itself and infect computer systems.二、通讯技术(Communication Technologies)1. Broadband(宽带)- A high-speed internet connection that can transmit large amounts of data simultaneously.2. Cellular network(移动通信网络)- A wireless network that allows mobile devices to connect to the internet.3. GPS(全球定位系统)- A navigation system that uses satellites to determine the precise location of a device or user.4. Modem(调制解调器)- A device that modulates and demodulates analog signals to enable digital data transmission over telephone or cable lines.5. Satellite(卫星)- An object that orbits around a planet or star and is used for communication or navigation purposes.6. Telecommunication(电信)- The transmission of information over long distances using electronic devices.7. Video conference(视频会议)- A communication session between two or more participants in different locations, conducted through video and audio transmissions.8. VoIP(网络电话)- Voice over Internet Protocol, a technology that allows voice communication over the internet.三、机器和设备(Machines and Devices)1. 3D printer(3D打印机)- A device that creates three-dimensional objects by adding layers of material.2. Drone(无人机)- An unmanned aerial vehicle that can be controlled remotely or autonomously.3. Robot(机器人)- A programmable machine that can perform tasks automatically or with human guidance.4. Sensor(传感器)- A device that detects and responds to physical inputs, such as light, heat, or motion.5. Smartphone(智能手机)- A mobile phone with advanced features and connectivity to the internet.6. Virtual reality(虚拟现实)- A computer-generated simulation that immerses the user in a virtual environment.7. Wearable device(可穿戴设备)- A technology device that can be worn on the body, such as a smartwatch or fitness tracker.8. X-ray machine(X射线机器)- A device that uses electromagnetic radiation to produce images of the internal structure of an object or body.四、能源与环境技术(Energy and Environmental Technologies)1. Biofuel(生物燃料)- Fuel derived from renewable biological sources, such as plant biomass or animal waste.2. Carbon footprint(碳足迹)- The amount of greenhouse gases produced by human activities, measured in units of carbon dioxide (CO2) equivalent.3. Renewable energy(可再生能源)- Energy derived from natural resources that are replenished, such as sunlight, wind, or water.4. Solar panel(太阳能电池板)- A device that converts sunlight into electricity.5. Sustainable(可持续发展的)- Describes practices and technologies that meet the needs of the present without compromising the ability of future generations to meet their own needs.6. Waste management(废物管理)- The collection, transportation, and disposal of waste materials in an environmentally responsible manner.7. Wind turbine(风力发电机)- A device that converts wind energy into electricity.总结:通过学习科技英语词汇,我们可以更好地理解和应用科技知识,与他人进行有效的沟通和交流。

Network Information Security Technologies

Network Information Security Technologies

Network Information SecurityTechnologiesIn the age of digitalization, the importance of network information security technologies cannot be overstated. As businesses, governments, and individuals increasingly rely on digital networks to store, transmit, and access critical information, the need for robust security measures has become paramount. This article aims to provide a comprehensive overview of network information security technologies, discussing their importance, types, and applications.Types of Network Information Security Technologies1. Firewalls: Firewalls are a crucial component of network security, acting as a barrier between a trusted internal network and the untrusted external network (typically the internet). They filter incoming and outgoing network traffic based on security rules, blocking unauthorized access and preventing malicious actors from penetrating the network.* Example: A company implements a firewall to protect its internal network from external threats. By carefully configuring the firewall rules, the company ensures that only authorized traffic can pass through, reducing the risk of data breaches.2. Intrusion Detection and Prevention Systems (IDS/IPS): These systems monitor network traffic for suspicious or malicious activity, such as unauthorized access attempts or malware infections. IDS/IPS can detect and alert administrators to potential threats, while some systems can also take proactive measures to block or mitigate attacks.* Example: An educational institution deploys an IDS/IPS to monitor traffic on its network. When the system detects an unusual pattern indicating a potential attack, it immediately alerts the IT team, allowing them to investigate and take action before any damage occurs.3. Encryption Technologies: Encryption is a crucial tool for protecting sensitive data from unauthorized access. By encrypting data, organizations can ensure that even if the data is intercepted by a third party, it cannot be easily decrypted and understood.* Example: A healthcare provider uses encryption to secure patient records stored on its network. By encrypting the data, the provider ensures that even if the network is compromised, the sensitive information remains protected.4. Access Control and Identity Management: These technologies allow organizations to manage and control who can access specific resources on their networks. By implementing strong access controls and identity management systems, organizations can ensure that only authorized individuals can access sensitive data or perform critical tasks.* Example: A financial institution implements multi-factor authentication for access to its online banking system. This means that users must provide multiple pieces of evidence (such as a password, a PIN, and a one-time passcode sent to their mobile phone) to gain access, greatly reducing the risk of unauthorized access.Applications of Network Information Security TechnologiesNetwork information security technologies are crucial in various sectors, including:1. Financial Services: Financial institutions handle sensitive customer data and transactions, making them prime targets for cybercriminals. Strong network security measures are essential to protect against fraud, data breaches, and financial losses.2. Healthcare: Healthcare providers store vast amounts of sensitive patient data on their networks. Ensuring the security of this data is crucial to maintaining patient trust and complying with regulatory requirements.3. Government and Defense: Governments and defense organizations handle highly sensitive information that could have national security implications if compromised. Robust network security measures are essential to protect against cyberattacks and espionage activities.In conclusion, network information security technologies play a pivotal role in protecting critical information and assets in today's digital world. By understanding the types and applications of these technologies, organizations can make informed decisions about their network security needs and take proactive measures to mitigate the risk of cyberattacks and data breaches.。

firewall technology

firewall technology

AbstractThe rapid development of the Internet brought great convenience to people's life, but at the same time, the Internet is faced with an unprecedented threat. Therefore, how to use effective and feasible ways to keep the danger of the Internet within the acceptable range attracts more and more attention. And how to implement prevention strategies depends first and foremost on the security of the current system. Therefore, the risk assessment in the independent elements of the network security ,including firewall, vulnerability scanning, intrusion detection and anti-virus, is essential.Firewall is a more mature current network security technology. Its security relates directly to the users' vital interests. As for the independent elements of network security ---the firewall technology, through the analysis of the log file on the firewall, the design of mathematical model and prototype software, the points system, and the judgement of the system's security level, we can achieve the network security risk assessment of the destination network, and provide scientific evidence for the improvement of the system's security.Key Words:Network Security,F irewall,P revention Strategy,ContentChinese abstract................................................... .. (Ⅰ)English abstract (Ⅱ)Content (1)1.Introduction (4)1.1Research background (4)1.2Research purposes (4)1.3Thesis structure (6)work Security (7)2.1Network security problem (7)2.1.1 Main threats to network security (7)2.1.2Factors affecting network security (8)2.2Measures of network security (8)2.2.1Perfecting legislation of computer safty (9)2.2.2 Key technologies for network security (9)2.3Proper measures for network management (10)3.Summery of Firewall (12)3.1Firewall concept (12)3.1.1 Traditional firewall introduction (13)3.1.2 Intelligent firewall introduction (14)3.2Firewall functions (15)3.2.1 The major functions (15)3.2.2 Intrusion detection (16)3.2.3 Virtual private network (18)3.2.4 Other functions (18)3.3.Firewall principles and classification (18)3.3.1Packet filter (18)3.3.2Application level proxy (19)3.3.3Proxy service (20)3.3.4Hybrid firewall (21)3.4.Packet-filtering Technologies (21)3.4.1Table structure (22)3.4.2Traditional packet filtering (23)3.4.3Dynamic packet filetering (25)3.4.4Deep packet inspection (26)3.4.5Flow filtration technology (27)4.Firewall Configurations (30)4.1Hardware connection and impletation (30)4.2 Feature set (31)4.3Configuration and implementation (31)5.The Development Trend of Firewall (34)5.1Firewall technologies (34)5.2Firewall architectures (35)4.3Firewall system management (36)5.Conclusion (37)6.Bibliography (38)7.Acknowlegements (40)1.Introduction1.1Research backgroundWith the proliferation and development, and purticularly the extensive use of the Internet, computer application develops into a greater extent and depth. Meanwhile, we have to notice that although the network has many powerful functions, it is also vulerable to the attacks. According to FBI statistics, the annual economical loss resulted by network security is up to 7.5 billion dollars in the United States, and a computer intrusion through Internet occurs every 20 seconds in the world. In China, hacker attacks and the damage caused by computer viruses also resulted in great economical loss. While utilizing the advantages of the network, we should never neglect the network security. So, how to build a safe network system deserves our attention and research.1.2Research purposesThe firewall technologies have emerged in recent years and served as solutions to the security problems of the personalnetwork in the Internet age. Firewall has strong practicability and pertinence. It provides complete solutions to the network security for the personal users, and it can effectively control the PC users to send and receive information on the Internet. Based on personal needs, the users can setup parameters to control the information communication between their computers and the Internet and stop the attacks from the malicious information. Such as ICMPnood attack,chat-room bomb, Trojan decoding the message and changing the email passwords. Besides, firewall can record other system's attempted visit to the local system in a real-time mode, so that when connecting to the Internet, the computer can avoid the attacks from the Internet and the security threat of information leakage.Firewall can protect us from hacker attacks in a real-time mode when we surf on the Internet. We can create firewall rules according to our needs, in order to control all the connections from the Internet to PC and from PC to the Internet and prevent the intrusion. Firewall can effectively stop different malicious attacks and protect the information. The information leakage prevention can assure us of safe Internet surfing and check the spread of the email viruses. Email content inspection can monitor the email system in a real-time mode and stop all malicious actions upon the hardwares.Personal firewall refers to that on the stand-alone Windows system, we take some safety prevention measures to protect the host. Personal firewall is a small security protect software and is stand-alone operating-system-oriented . It filters the message of TCP, UDP, and ICMP under certain rules, monitor the network information flow and system process, and prevent the malicious attacks. In the current market, most firewalls are gateway firewalls. Although they have many powerful functions, these firewalls, based on the hypothesis that the network is safe and reliable and all the threats is from the outside Internet, can only prevent the threats from the outside Internet and cannot stop the threats within the network, Therefore, it is hard to achieve safe communication within the Local-Area Network of an organization, and to resolve the security problems of the dial-up network users' computer. And most personal users are placed in a network without security protection while surfing on the Internet.The personal network users mainly use Windows operating system, but the Windows operating system, purticularly the WindowsXP system, has low security. Various Windows loopholes have been announced continuously, and host attacks have been rising.The attacks are generally realized though the security loopholes of the operating system and the communicationprotocols. For example, the fake IP packages cheat the both sides of communication:sending a great number of data packets to the host to exhaust the source in the host, and blue screen. Therefor, it is neccessry to develop effective personal firewalls to protect the safe communication of the host.1.3Thesis structureThe arrangement of the next chapters should be as follows:2.Analysis of network security problems; the major threats to the network security; the factors affecting network security; and the key technologies for network security protection.3. Presentations of the firewall technologies, like the firewall design principles and functions as well as packet filter technology.4. Take the F100 firewall of H3C H3C for example to introduce the methods of firewall configuration.5. Elaberating the trend of firewall development.work Security2.1Network security problemsSecurity is a mechanism by which only the authorized person has the right to use the related resoureces. The definition of computer security in China is that the computer hardware, software, and data are protected and will no be destroyed, changed or exposed due toany accidental or malicious reasons and the system can work normally all the time.Technologically, computer security can be divided into three catagories.1. Physical security. It ensures the safety of the hardwares and softwares.2. Operating environment security. It can garantee that the computer can work continously in good environment.3. Information securtiy. It ensures that the information will not be illegally read, changed or divulged.With the development of the network, the computer security issue is extended to the computer network.2.1.1The major threats to the network securtiyIt is generally recognized that the major security threats to the computer network system mainly comes from the computer viruses, hacker attacks and denial of service attacks.1.The computer viruses. At present, the number of active viruses is up to 14.000. The computer viruses invade the network and damage the network resourses. As a result, the network cannot work properly and even collapse.2.Hacker attacks. Hacker attacks means that hackers enter thenetwork and use the resourses illegally, for example, illegal activities through covert channel; using anonymous user access to launch attacks; obtaining the net users' account and password through network monitoring; illegally obtaining the transmitted data on the Internet; and breaking through the firewalls.3.Denial of service attack, for example, mail bomb. Mail bomb refers to that the user receives a large number of useless emails in a short time, which affects the normal business operation, and even leads to the system shutdown and network collapse in severe cases.Specifically, the security threats of the network system mainly represents as follows: identity theft, unauthorized access, data interception, denial of service, viruses and malicious attacks, and impersonating legitimate users.2.1.2The factors affecting network security1Single computer safetyThe factors affecting the single computer safety include model selection while you purchase the computer, the computer operating environment (voltage, humidity, dust prevention, strong electromagnetic field, and natural disasters), and the computer operation.work securityThe factors affecting network security includes node safety, data safety (saving and transmission of the data) , and the file safety.2.2 Measures of network securityNetwork information security is a complicated system, involving several aspects, A complete network information security system should include at least three classes of measures.The first is the external soft environment, like legal policies, regulations, and security education. The second is the technologies, such as information encryption, storing and transmission, identity anthentification, firewalls, and network viruses prevention. The third is the management, including technological and social measures. The major measures are providing capability to change the security policies in the real-time mode, monitoring the organization's security status in a real-time mode, carrying on the vulnerability check of the current security system to prevent potential threats. The three classes of measures are dispensible. Because the leagal policies are the cornerstone of security, technologies the guarantee of security and management and auditing the defense line of security.2.2.1Perfecting legislation of computer safetyOur country has worked out a series of rules and regulationsabout network security management. But at present, legislation concerning this field is far from meeting the needs of increasing development. On the basis of foreign and domestic evaluation of legislation against computer crimes, we should perfect our computer crime legislation in order to provide a powerful guarantee for the healthy and orderly development of the computer information network in our country.2.2.2 Key technologies for network security1. Data encryptionEncryption is the process of transforming plaintext into ciphertext, so that the unauthorized people cannot understand it. There are two major encryption types, namely, private key and public key encryptions.2.AuthentificationAuthentification of valid users can prevent the invalid users from obtaining the access to the organization information system. Besides, this mechanism can also keep the valid users away from the information they are not authorized to view.3.Firewall technologiesFirewall is the internal network barrier to block the influence from the outside insecurity factors, and its function is to avoid the outside network users' unauthorized access. Currently, the majorfirewall technologies include packet filter, application gateway, and screened subnet. However, firewall technologies have their shortcomings in network security and defence. For example, firewall cannot prevent the internal attacks, cannot replace the anti-virus softwares, and is hard to prevent the attacks from the Rebound Port Trojan Horse.4.Detecting systemIntrusion detection is a hotspot of the research on network security, and it is an active preventative technology, providing a real-time protection against internal intrusion, external intrusion and wrong operation, and stopping the attacks before the network system gets damaged.With the development of the time, the intrusion detection technology will move toward the following three directions, namely, distributed intrusion detection, intelligent intrusion detection, and all-embracing security solutions.5.Anti-virus techniquesWith the development of the computer technologies, computer viruses become increasingly complicated and advanced. Computer virus prevention is not just a product, a strategy, or a system. Instead, it is a comprehensive system integrating hardwares, softwares, network, and the interconnections andinterfaces between them.6.File system securityIn the network operating system, permission is a key concept, because access control is achieved in two ways, locally and remotely. While building the file permission, we must first implement New Technology File System, NTFS, in Windows 2000. In NTFS, you can use Windows Explorer to specify the users' level of permission. You need to know the permissions that can be assigned, and that some rules in the daily activities treat permissions. Windows 2000 operating system allows to build complicated file and file folder permissions, by which you can realize the necessary access control.2.3 Proper measures for network management1. Strengthen the net users and relevant personnels' security awareness, professional ethics, enterprise, the responsibility education and relevant technical training.2. Build the perfect security management system and regulations to encourage and monitor the administrators and operators.3 The management measures should be standard, and scientific.3. Summery of FirewallWith the rapid development of the Internet, network application involves more and more fields and the important and sensitive data on the network is increasing, however, due to hacker attacks and network viruses, network security problems becomes increasing serious. Therefore, protecting the network resource from unauthorized access and preventing the spread and infection of viruses are of great importance. Currently, firewall remains the effective means to safeguard local networks. Firewall technologies contains packet filter and application proxy, among which the former was firstly developed and has been widely used.3.1.Firewall conceptFirewall is a barrier between the protected network and the outside network to prevent the unpredictable and potential destructive intrusion. Firewall refers to the combinations of a series of components and the only entrance and exit of information between different networks (like the reliable organization intranet and the unreliable public network) or security domains. According to the security policies of this organization, firewall can control (permit, refuse, and monitor) the information flow entering or exiting the network, and itself has a relatively strong attack power. Firewall, providing information security service , is the infrastructure for achieving network and information safety. Logically, firewall is aseparator, a limiter, and a analyzer, effectively monitoring all activities between the Internet and the internal network, and ensure the safety of the later.3.1.1 Traditional firewall introductionThe current firewall technologies have gone through five development stages, both technologically and on the process of product development. Figure1 shows firewall's simple history of development.The first-generation firewallThe first generation of firewall almost came into being at the same time with routers. It adopted packet filter technology.The second and third-generation firewallIn 1989, Dave Presotto and Howard Trickey from Bell Laboratory developed the second generation of firewall, calling the circuit level firewall. And meanwhile they put forward the initial structure of the third-generation firewall, the application level ( the proxy) firewall.The fourth-generation firewallIn1992, Bob Braden from USC information college developed the fourth-generation firewall based on the dynamic packet filter technology. In 1994, an Israeli company called CheckPoint firstly built this technology into commercial products.The fifth-generation firewallIn 1998, NAI company came up with an Adaptive Proxy technology, which was applied into its product, Gauntlet Firewall for NT.This firewall, granting brand-new meaning to the proxy firewall, can be called the fifth generation of firewalls.But the traditional firewalls did not resolve the major security problems in the current network. The present three major network security problems include network attacks represented by DDOS, virus spread represented by Worm, and content control represented by junk e-mails. The three main security problems account for over 90% of the network safety problems. However, the traditional firewalls can do nothing about the three problems for the following three reasons.The first reason is the limitation of computing power. The traditional firewall is based at the cost of high-intensity inspection.The higher the intensity of the inspection is, the greater cost the computer has to bear. The second reason is that the access control mechanism of the traditional firewall is a simple filter mechanism. It is a simple filter with certain criterias, has no intelligent functions, and could not detect the complex attacks. The last reason is that the traditional firewalls cannot differentiate the good behaviour from the malicious ones, This determines that the traditional firewalls cannot handle the malicious attacks.Now the firewall is moving toward the directions of distribution and intelligence, among which the later can settle the earlier problems very well.。

信息安全术语

信息安全术语

信息安全技术术语(中英文)1。

0 Network Security 网络安全1。

1 Implementsecurity configuration parameters on network devices and othertechnologies. 在网络设备和其他设备上实施安全配置参数Firewalls 防火墙Routers 路由器Switches 交换机Load Balancers 负载均衡Proxies 代理Web security gateways Web安全网关VPN concentrators VPN网关NIDS and NIPS 网络入侵检测与网络入侵防范* Behavior based 基于行为* Signature based 基于特征* Anomaly based 基于异常* Heuristic 启发式Protocol analyzers 协议分析仪Spam filter 垃圾邮件过滤UTM security appliances 统一威胁管理* URL filter URL过滤* Content inspection 内容检查* Malware inspection 恶意软件检查Web application firewall vs. network firewallWeb应用防火墙与网络防火墙Application aware devices 应用端设备* Firewalls 防火墙* IPS 入侵防御* IDS 入侵检测* Proxies 代理1.2 Given a scenario,use secure network administration principles. 给定一个场景,应用安全网络管理原则Rule-based management 基于规则的管理Firewallrules 防火墙规则VLAN management VLAN管理Secure router configuration 安全路由配置Access control lists 访问控制列表Port Security 端口安全802。

企业网络安全解决方案的设计

企业网络安全解决方案的设计

摘要计算机网络的发展和技术的提高给网络的安全带来了很大的冲击,Internet的安全成了新信息安全的热点。

网络安全,是计算机信息系统安全的一个重要方面。

如同打开了的潘多拉魔盒,计算机系统的互联,在大大扩展信息资源的共享空间的同时,也将其本身暴露在更多恶意攻击之下。

如何保证网络信息存储、处理的安全和信息传输安全的问题,就是我们所谓的计算机网络安全.信息安全是指防止信息财产被故意的或偶然的非法授权泄露、更改、破坏或使信息被非法系统辩识、控制;确保信息的保密性、完整性、可用性、可控性.信息安全包括操作系统安全、数据库安全、网络安全、病毒防护、访问控制、加密和鉴别七个方面。

设计一个安全网络系统,必须做到既能有效地防止对网络系统的各种各样的攻击,保证系统的安全,同时又要有较高的成本效益,操作的简易性,以及对用户的透明性和界面的友好性。

针对计算机网络系统存在的安全性和可靠性问题,本文从网络安全的提出及定义、网络系统安全风险分析,网络攻击的一般手段,企业局域网安全设计的原则及其配置方案提出一些见解,并且进行了总结,就当前网络上普遍的安全威胁,提出了网络安全设计的重要理念和安全管理规范并针对常见网络故障进行分析及解决,以使企业中的用户在计算机网络方面增强安全防范意识,实现了企业局域网的网络安全. 关键词:网络安全;路由器;防火墙; 交换机; VLANA bstractThe development of computer networks and technologies to enhance network security is a big blow, Internet security has become a new hotspot of information security。

Network security is the security of computer information systems in an important aspect. Like opening of the Pandora's Box, the computer systems of the Internet,greatly expanded information resources sharing space at the same time, will be its own exposure to the more malicious attacks under. How to ensure that the network of information storage, processing and transmission of information security security,is the so-called computer network security. Information security is to prevent information from the property have been deliberately or accidentally leaked authorized illegal, altered,damage or illegal information system identification, control;ensure confidentiality, integrity, availability, controllable。

国内外主流防火墙分析

国内外主流防火墙分析

网盾防火墙与国内外主流防火墙分析报告一.防火墙产品类型发展趋势在防火墙十多年的发展中,防火墙厂家对防火墙的分类一直在变化,各个厂家对自己的防火墙产品有不同的标榜。

但在我看来,防火墙发展的总趋势都是集中在寻找防火墙性能和功能的平衡点。

下面是五种典型的现行的防火墙种类。

(一.)包过滤防火墙传统的包过滤对包的检测是工作在网络层,它只是通过逐个检查单个包的地址,协议以及端口等信息来决定是否允许此数据包通过。

包过滤的主要优点是由高性能和易于配置,因此尽管包过滤的安全性低,许多厂家仍然不放弃包过滤类型,而且对包过滤进行了大量的功能扩展,如添加代理功能,用户认证,对话层的状态检测等以提高包过滤的安全性能,以求做到保证速度和安全性兼得。

(二.)应用代理防火墙应用级防火墙主要工作于应用层。

它主要的优点是通过完全隔离内网和外网的通信以及细粒度的内容检测可以达到很强的安全性能。

但是它的缺点也很突出,首先它对网络性能影响很大,其次是必须为每一种服务实现一个代理所造成的开发上的麻烦,最后是应用代理防火墙对用户配置所造成的麻烦。

所以应用代理防火墙的厂商也不断的想办法提高自己的性能增强自己的竞争力,另一方面也逐步向透明代理过渡以方便用户的使用。

(三.)混合型防火墙(Hybrid)由于希望防火墙在功能和处理上能进行融合,保证完善的应用。

许多厂家提出了混合型防火墙的概念。

他们认为混合型防火墙应该是动态包过滤和透明代理的有机结合,可以做到用户无需知道给他提供服务的到底是用了那些技术,而防火墙根据不同的服务要求提供用户的使用要求和安全策略。

而且为了保证性能只有必须使用应用代理才能实现的功能才使用代理。

(四.)全状态检测防火墙(Full State Inspection)这是由一个知名防火墙厂家Checkpoint提出的一种新型防火墙,据Checkpoint关于firewall-1的技术文档介绍,该种防火墙既能具有包过滤的功能又能具有代理防火墙的安全性。

罗克威尔自动化与以太网 IP技术:连接工厂网络的多种选项说明书

罗克威尔自动化与以太网 IP技术:连接工厂网络的多种选项说明书

Stratix 5900 Camera CameraIn this illustration, both lines have the same private IP addresses (ControlLogix-192.168.1.3, Point I/O-192.168.1.4, PanelView Plus 6-192.168.1.5) on their respective local control network. This allows the lines to be exact duplicates of each other, reducing development and support time. For those nodes that need to communicate to the public plant network (ControlLogix and PanelView Plus 6) the NAT mapping functionality in each of the three products shown allows these nodes to appear as a node on the plant network.For example, if a Server PC on the public plant network (IP 172.16.10.1) needs tocommunicate to the ControlLogix on Line 1, it sees that ControlLogix as being on the public plant network at 172.16.10.13Only the local control network nodes you select to map are accessable from the public plant network. The Point I/O is not accessable in this illustration.NAT IllustrationStratix 5700 with NAT Applications requiring managed switch plus NAT capability 9300-ENAApplications with Embedded or Unmanaged SwitchesCamera Camera In this illustration, the plant wishes to segment nodes on each of the two physical networks (Assembly Line 1 & 2) into 4 logical networks (VLANs 10, 20, 30, 40). This is to isolate devices for functional and/or traffic considerations.The Stratix 5700 Layer 2 switch supports creating these VLANs.VLAN 10 has a ControlLogix, it’s Point I/O and a PanelView Plus 6. VLAN 20 has the same. These networks are isolated from each other.VLAN 30 has a Supervisory Controller PC – again isolated from the others VLAN (10 or 20 and 40) networks are on the same cable.VLAN 40 illustrates another key advantage of VLANs. It contains streamingvideo cameras used for remote machine diagnostic support. These generate a lot of traffic, but since they are on a separate VLAN they have no impact on the local traffic of VLANs 10 & 20 or PC VLAN 30.If a device on one VLAN needs to communicate to another (the SupervisoryController PC needs to communicate to the Assembly Line 1 ControlLogix), the level 3 routing capability in the Stratix 8300 Layer 30 switch supports setting up this VLAN 30 to VLAN 10 link.VLAN IllustrationCatalog #Description1783-BMS10CL Stratix 5700 Layer 2 Managed Switch, 10 Ports 1783-RMS10T Stratix 8300 Layer 3 Managed Switch, 10 Ports 1783-MS10T Stratix 8000 Layer 2 Managed Switch, 10 Ports 1783-SR Stratix 5900 Security Appliance1756-EN2TSC ControlLogix Secure Communications Module 9300-ENA Ethernet Network Appliance1783-US08TStratix 2000 Unmanaged Switch, 8 PortsAdditional ResourcesENET-PP005B-EN-E Stratix 5700 Industrial Ethernet Switch Product Profile ENET-UM003A-EN-P 1756-EN2TSC EtherNet/IP Secure Communication User ManualENET-AT004B-EN-E Segmentation Methods within the Cell / Area Zone ENET-WP025-EN-E Scalable Secure Remote Access Solutions for OEMs ENET-WP031A-EN-E Design Considerations for Securing Industrial AutomationENET-TD001-EN-P Converged Plantwide Ethernet (CPwE) Design and Implementation Guide (DIG)ENET-QR001-EN-E Stratix Switch Reference Chart ENET-QR002-EN-E Stratix 5700 Reference ChartGMSP-PP001-EN-E 9300-ENA Network Address Translation Device Product Profile SECUR-AT001A-EN-EIndustrial Security Best PracticesPublic Plant Network802.1x Security - An IEEE standard for access control and authentication. It can be used to track access to network resources and helps secure the network infrastructure.ACLs (Access Control Lists) - allow you to filter network traffic. This can be used to selectively block types of traffic to provide traffic flow control or provide a basic level of security for accessing your network.IPSec (IP Security) - A framework of open standards that provides data confidentiality, data integrity, and data authentication between participating peers.Firewall - Asecurity system that controls the incoming and outgoing network traffic by analyzing the data packets and determining whether they should be allowed through or not, based on a rule set. A firewall establishes a barrier between a trusted, secure internal network and another network (e.g., the Internet) that is not assumed to be secure and trusted.Unified Threat Management (UTM) - An evolution of the traditional firewall into an all-inclusive security product that has the ability to perform multiple security functions in one single appliance: network firewalling, network intrusion prevention and gateway antivirus (AV), gateway anti-spam, VPN, content filtering, load balancing, data leak prevention and on-appliance reporting.VPN (Virtual Private Network) - A network that uses primarily public telecommunication infrastructure, such as the Internet, to provide remote users an access to a central organizational network. VPNs typically require remote users of the network to be authenticated, and often secure data with encryption technologies.Reference Architecture Web Page/rockwellautomation/products-technologies/network-technology/architectures.page。

网络安全专业术语对照表

网络安全专业术语对照表

网络安全专业术语对照表导言:随着互联网和信息技术的快速发展,网络安全问题成为了当前亟待解决的重要课题。

在网络安全领域,专业术语的准确理解和使用非常重要。

本文通过对网络安全领域的专业术语进行解释和对照,旨在帮助读者更好地理解和运用网络安全术语。

一、密码学1. 加密算法(Encryption Algorithm)加密算法是指将明文转化为密文的一组数学运算和方法,确保数据在传输和存储中的安全性。

- 对称加密算法(Symmetric Encryption Algorithm):采用相同密钥进行加密和解密的算法,如DES、AES等。

- 非对称加密算法(Asymmetric Encryption Algorithm):采用公钥和私钥进行加密和解密的算法,如RSA、ECC等。

2. 数字签名(Digital Signature)数字签名是在信息传输过程中用于验证数据完整性和真实性的技术手段,通过加密和验证手段确保数据不被篡改。

- 数字证书(Digital Certificate):由可信第三方机构颁发,用于证明数字签名真实有效的电子文档。

二、网络防御1. 防火墙(Firewall)防火墙是用于保护内部网络与外部网络之间信息传输的安全设备,它根据预设的安全策略对网络流量进行过滤和监控,阻止潜在的网络攻击。

- 包过滤防火墙(Packet Filtering Firewall):根据网络数据包的源地址、目标地址、协议和端口等信息进行过滤和判断,对不符合策略的数据包进行阻止。

- 应用层网关(Application Gateway):基于应用层协议对网络数据进行过滤,具有更高级别的安全性。

2. 入侵检测系统(Intrusion Detection System)入侵检测系统是一种用于监测和识别网络中的入侵行为的安全设备,通过实时监测网络流量和系统日志等信息,及时发现和报告潜在的攻击。

- 签名检测(Signature-based Detection):通过事先定义的攻击特征(签名)进行匹配和识别攻击行为。

信息通信专业英语词汇及常用英语口语

信息通信专业英语词汇及常用英语口语

信息通信专业英语词汇及常用英语口语以下是一些信息通信专业的英语词汇和一些常用的英语口语表达,供参考:信息通信专业英语词汇:munication Networks:•Wired Network: 有线网络•Wireless Network: 无线网络•LAN (Local Area Network): 局域网•WAN (Wide Area Network): 广域网2.Telecommunications:•Telecommunication Systems: 电信系统•Fiber Optic Communication: 光纤通信•Satellite Communication: 卫星通信3.Data Transmission:•Data Rate: 数据传输速率•Bandwidth: 带宽•Modulation: 调制•Demodulation: 解调4.Internet Technologies:•Internet Protocol (IP): 互联网协议•TCP/IP (Transmission Control Protocol/Internet Protocol): 传输控制协议/互联网协议•URL (Uniform Resource Locator): 统一资源定位符5.Wireless Communication:•Mobile Communication: 移动通信•5G Technology: 5G 技术•Bluetooth: 蓝牙•Wi-Fi: 无线网络6.Security:•Cybersecurity: 网络安全•Encryption: 加密•Firewall: 防火墙•Authentication: 身份验证7.Hardware and Software:•Router: 路由器•Switch: 交换机•Protocol: 协议•Application Software: 应用软件8.VoIP (Voice over Internet Protocol):•VoIP Call: 互联网电话•SIP (Session Initiation Protocol): 会话初始协议常用英语口语表达:1.Greetings:•"Hello! How are you doing?"•"Good morning/afternoon/evening."2.Making Requests:•"Could you please explain that in more detail?"•"Would you mind providing some more information?"3.Giving Opinions:•"In my opinion,..."•"From my perspective,..."4.Describing Technology:•"This device operates on the latest technology."•"The software is user-friendly and intuitive."5.Problem-Solving:•"Let's troubleshoot the issue together."•"We need to identify the root cause of the problem."6.Meetings and Presentations:•"I'd like to present the key findings of our project."•"Are there any questions or concerns?"7.Expressing Agreement/Disagreement:•"I completely agree with your point."•"I see what you're saying, but I have a different perspective."8.Closing a Conversation:•"It was great talking to you."•"Let's keep in touch. Have a great day!"这些词汇和表达方式应该能够涵盖信息通信专业中的许多常见主题和情境。

计算机网络安全论文

计算机网络安全论文

计算机网络安全的探讨摘要:本文阐述了计算机网络安全的现状及发生的原因,并提出了应采取的几种防护技术。

关键词:计算机网络;网络安全;防火墙技术中图分类号:tp393 文献标识码:a 文章编号:1007-9599 (2011) 22-0000-01computer network security studyyu xinguo,liu jia(hubei chutian radio and tv information networkco.,ltd.jingmen branch,jingmen 448000,china)abstract:this paper describes the status of computer network security and the causes,and proposed to be taken several protection technologies.keywords:computer networks;network security;firewall technology一、计算机网络安全的现状计算机网络安全是指利用网络管理控制和技术措施,保证在一个网络环境里,数据的保密性、完整性及可使用性受到保护。

但如果这种保护受到了威胁,达不到保护的目的,那我们的工作和生活将会受到很大的影响。

中国国家互联网安全中心在大连举行的“计算机网络安全年会”上表示,2010年中国共有近3.5万家网站被黑客篡改,其中被篡改的政府网站达4635个,比2009年上升67.6%,政府网站安全防护较为薄弱。

此外,金融行业网站频频遭遇“网络钓鱼”,成为不法分子骗取钱财和窃取隐私的重点目标。

2010年,国家互联网应急中心共接收网络钓鱼事件举报1597件,较2009年增长33.1%。

被仿冒的网站按事件次数排在前十位的中有9家是金融或经济机构。

其中,包括美国电子商务网站、中国香港汇丰银行、中国工商银行。

工控系统网络安全防护指南解读

工控系统网络安全防护指南解读

工控系统网络安全防护指南解读1.工控系统网络安全防护指南对于企业的信息安全至关重要。

The industrial control system network security protection guidelines are essential for the information security of enterprises.2.该指南提供了网络安全的最佳实践方法和建议。

The guidelines provide best practices and recommendations for network security.3.它包括了密码管理、网络防火墙、入侵检测等方面的内容。

It includes aspects such as password management, network firewall, intrusion detection, etc.4.企业应该严格执行工控系统网络安全的最佳实践。

Enterprises should strictly adhere to the best practices for industrial control system network security.5.对于网络漏洞和威胁,企业应该保持警惕。

Enterprises should remain vigilant against network vulnerabilities and threats.6.定期进行网络安全漏洞扫描和修复工作。

Regularly conduct network security vulnerability scanning and remediation.7.保护网络通信数据的机密性和完整性是至关重要的。

Protecting the confidentiality and integrity of network communication data is crucial.8.指南强调了对设备和系统进行更新和维护的重要性。

网络安全行业术语英文

网络安全行业术语英文

网络安全行业术语英文网络安全行业术语英文:1. Malware(恶意软件)- Abbreviation for malicious software, refers to any type of software that is designed with malicious intent, such as viruses, worms, Trojan horses, ransomware, spyware, etc.2. Firewall(防火墙)- A network security device that monitors incoming and outgoing network traffic based on predefined security rules, preventing unauthorized access to or from a private network.3. Encryption(加密)- The process of converting plain text into cipher text, making the information unreadable to anyone without the proper decryption key.4. Phishing(钓鱼)- A cyber attack where attackers try to deceive individuals into disclosing sensitive information, such as passwords or financial information, by posing as trustworthy entities in emails or websites.5. Two-factor authentication(双因素认证)- A security measure that requires users to provide two types of identification factors, such as a password and a biometric scan or a security token, to gain access to a system or account.6. Vulnerability(漏洞)- A weakness or flaw in a system or software that can be exploited by attackers to gain unauthorized access, manipulate data, or disrupt normal operation.7. Patch(补丁)- A software update or fix that is released by vendors to address known vulnerabilities or bugs in their software, aiming to improve security or functionality.8. Intrusion Detection System (IDS)(入侵检测系统)- A network security tool that monitors network traffic, identifies suspicious or potentially malicious activity, and alerts network administrators to potential intrusions.9. Denial of Service (DoS)(拒绝服务)- An attack where an attacker overwhelms a target system or network with a flood of malicious traffic, rendering it unable to respond to legitimate requests.10. Brute-force attack(暴力破解)- An attack method in which an attacker tries all possible combinations of passwords or encryption keys until the correct one is found.11. Antivirus software(防病毒软件)- A software program designed to detect, prevent, and remove computer viruses and other malware from infected systems or networks.12. Social engineering(社交工程)- A technique used by attackers to manipulate individuals into divulging sensitive information or performing certain actions through psychological manipulation, deception, or impersonation.13. Zero-day vulnerability(零日漏洞)- A security vulnerabilitythat is unknown to software vendors or the public, allowing attackers to exploit it before a patch or fix is released.14. Intrusion Prevention System (IPS)(入侵预防系统)- Similar to an IDS, an IPS also monitors network traffic, but it can take action to prevent or block suspicious or malicious activity from compromising the network.15. Penetration testing(渗透测试)- The process of evaluating the security of a system or network by simulating real-world attack scenarios to identify vulnerabilities, weaknesses, or potential entry points.16. Cybersecurity incident response(网络安全事件响应)- The process of handling and responding to a cybersecurity incident in a systematic and organized manner, including detecting, containing, eradicating, and recovering from the incident.17. Data breach(数据泄露)- An incident where unauthorized individuals gain access to sensitive or protected data, leading to potential misuse, theft, or exposure of the data.18. Secure socket layer (SSL)(安全套接层)- A cryptographic protocol used to establish secure, encrypted connections between a web server and a client, ensuring the confidentiality and integrity of the data transmission.19. Network segmentation(网络分割)- The practice of dividinga computer network into smaller subnetworks called "segments" toisolate traffic and limit the impact of potential security breaches.20. Identity and access management(身份和访问管理)- A framework or set of processes and technologies used to manage and control user identities, access rights, and permissions in a network or system.。

毕业设计(论文)企业局域网网络规划与设计

毕业设计(论文)企业局域网网络规划与设计

摘要随着网络的逐步普及,公司网络的建设是公司向信息化发展的必然选择,公司网网络系统是一个非常庞大而复杂的系统,它不仅为综合信息管理和办公自动化等一系列应用提供基本操作平台,而且能提供多种应用服务,使信息能及时、准确地传送给各个系统。

提供消耗带宽的新内容和要求苛刻的多媒体应用要求您高效地使用带宽,这意味着您需要一个高速的、具有先进性的、可扩展的公司计算机网络以适应当前网络技术发展的趋势并满足公司各方面应用的需要。

而公司网工程建设中主要应用了网络技术中的重要分支局域网技术来建设与管理的,因此本毕业设计课题将主要以深蓝公司网络规划与设计过程可能用到的各种技术及实施方案为设计方向,为公司网的建设提供理论依据和实践指导。

关键字:局域网 VLAN 服务器防火墙AbstractWith the popularization network step by step, the campus network to the school building is the inevitable development of information technology choice, Campus Network System is a very large and complex system, not only for teaching modern, comprehensive information management and office automation such as a Series applications to provide basic operating platform, but also provide a wide range of applications, so that information can be promptly and accurately transmitted to the various systems. The campus network construction in the main applications of network technology to the important branch LAN technology to the construction and management, so this will be the main topic graduate design to the construction of QI SHAN middleschool campus local area network technologies may be used for the design and implementation of the programme direction, To the campus network and provide a theoretical basis and practical guidance.Keywords: Local area network VLAN Server Firewall目录绪论 (5)第一章前言1.1 公司网络系统建设目标,,,,,,,,,,,,,1.2 用户具体需求,,,,,,,,,,,,,,,,,,1.3 公司系统建设原则,,,,,,,,,,,,,,,,,,1.3.1 先进性,,,,,,,,,,,,,,,1.3.2 标准性,,,,,,,,,,,,,,,,,,,,,1.3.3 兼容性,,,,,,,,,,,,,,,,,,1.3.4 可升级和可扩展性,,,,,,,,,,,,,1.3.5 安全性,,,,,,,,,,,,,,,,,,,,1.3.6 可靠性,,,,,,,,,,,,,,,,,,,1.3.7 易操作性,,,,,,,,,,,,,,,,,,,,1.3.8 可管理性,,,,,,,,,,,,,,,,,,第二章综合布线方案2.1 需求分析,,,,,,,,,,,,,,,,,,,,,,,2.2 综合布线系统的结构,,,,,,,,,,,,,,,,,,2.3 系统总体设计,,,,,,,,,,,,,,,,,2.4 系统结构设计描述,,,,,,,,,,,,,,第三章网络设计方案3.1 网络设计需求,,,,,,,,,,,,,,,,,,,3.2 总体方案设计策略,,,,,,,,,,,,,,3.3 公司园区结构示意图,,,,,,,,,,,,,,,3.4 网络设备选型,,,,,,,,,,,,,,,,,,,3.4.1 选型原则,,,,,,,,,,,,,,,,,,,,3.4.2 核心层交换机,,,,,,,,,,,,,,,3.4.3 接入层交换机,,,,,,,,,,,,,,,3.5 路由交换技术部分设计,,,,,,,,,,,,,,,,3.6 网络安全设计,,,,,,,,,,,,,,,,,,,第四章 Windows服务器解决方案4.1 WEB服务器、Mail服务器选型,,,,,,,,,,,,,4.2 FTP服务器角色:配置文件服务器,,,,,,,,,,,,,4.3 数据库服务器及磁盘阵列选型,,,,,,,,,,,,,第五章工程实施方案实习总结,,,,,,,,,,,,,,,,,,,,,,,,致谢,,,,,,,,,,,,,,,,,,,,,,,,,参考文献,,,,,,,,,,,,,,,,,,,,,,,,,,绪论公司信息化,是指将信息网络技术、计算机、Internet以及电子商务运用到企业的市场调研、产品研发、技术改造、质量控制、供应链、资金周转、成品物流等全过程,从而实现信息化。

华为防火墙基础技术

华为防火墙基础技术

l
USG6000系列产品是华为公司面向大中型企业和数据中心设计的 NGFW设 备。 USG6000基于业界领先的软、硬件体系架构,通过对应用、用户、内容、
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威胁、时间、位臵的全面感知,将网络环境清晰的映射为业务环境,提供
基于应用、用户的安全和带宽管理功能。在应用识别的基础上,提供强大 的IPS、AV和数据防泄漏能力,全面、高性能地防护企业信息安全。
Service-set端口集
policy 1
action deny
policy source address-set guest
policy destination address-set intranet policy service service-set intranet
policy 0
action permit policy source address-set guest policy destination address-set Internet policy service service-set Internet
路由模式
防火墙 工作模式
透明模式的接口一定无IP地址吗?
防火墙安全区域定义
缺省安全区域
─ 非受信区域Untrust ─ 非军事化区域DMZ ─ 受信区域Trust ─ 本地区域Local
邮件服务器 Web服务器 DMZ
ISP A
Untrust
ISP B
Local区域呢?
财务服务器 ERP数据服务器 OA服务器
IP数据报文 10.1.0.0/16
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rule deny tcp source 129.9.0.0 0.0.255.255 destination 202.38.160.0 0.0.0.255 destination-port equal www

SonicWall NSA系列网络安全应用机产品说明说明书

SonicWall NSA系列网络安全应用机产品说明说明书

The SonicWall Network Security Appliance (NSA) series providesmid-sized networks, branch offices and distributed enterprises with advanced threat prevention in a high-performance security platform. Combining next-generation firewall technology withour patented* Reassembly-Free Deep Packet Inspection (RFDPI) engine on a multi-core architecture, the NSA series offers the security, performance and control organizations require. Superior threat prevention and performanceNSA series next-generation firewalls (NGFWs) integrate advanced security technologies to deliver superior threat prevention. Our patented single-pass RFDPI threat prevention engine examines every byte of every packet, inspecting both inbound and outbound traffic simultaneously. The NSA series leverages on-box capabilities including intrusion prevention, anti-malware and web/URL filtering in addition to cloud-based SonicWall Capture multi-engine sandboxing service to block zero-day threats at the gateway. Unlike other security products that cannot inspect large files for hidden threats, NSA firewalls scan files of any size acrossall ports and protocols. The security architecture in SonicWall NGFWs has been validated as one of the industry’s best for security effectiveness by NSS Labs for five consecutive years. Further, SonicWall NGFWs provide complete protection by performingfull decryption and inspection of TLS/SSL and SSH encrypted connections as well as non-proxyable applications regardless of transport or protocol. The firewall looks deep inside every packet (the header and data) searching for protocol non-compliance, threats, zero-days, intrusions, and even defined criteria to detect and prevent hidden attacks that leverage cryptography, block encrypted malware downloads, cease the spread of infections, and thwart command and control (C&C) communications and data exfiltration. Inclusion and exclusion rules allow total control to customize which traffic is subjected to decryption and inspection based on specific organizational compliance and/or legal requirements. When organizations activate deep packet inspection functions such as intrusion prevention, anti-virus, anti-spyware, TLS/SSL decryption/inspection and others on their firewalls, network performance often slows down, sometimes dramatically. NSA series firewalls, however, feature a multi-core hardware architecture that utilizes specialized security microprocessors. Combined with our RFDPI engine,this unique design eliminates the performance degradation networks experience with other firewalls.In today’s security environment, it’s not enough to rely on solely on outside parties for threat information. That’s why SonicWall formed its own in-house Capture Labs threat research team more than 15 years ago. This dedicated team gathers, analyzes and vets data from over one million sensors in itsSonicWall Network SecurityAppliance (NSA) seriesIndustry-validated security effectiveness and performance formid-sized networksBenefits:Superior threat preventionand performance• Patented reassembly-free deeppacket inspection technology• On-box and cloud-based threatprevention• TLS/SSL decryption and inspection• Industry-validated securityeffectiveness• Multi-core hardware architecture• Dedicated Capture Labs threatresearch teamNetwork control and flexibility• Powerful SonicOS operating system• Application intelligence and control• Network segmentation with VLANs• High-speed wireless securityEasy deployment, setup andongoing management• Tightly integrated solution• Centralized management• Scalability through multiplehardware platforms• Low total cost of ownershipCapture Threat Network. SonicWall also participates in industry collaboration efforts and engages with threat research communities to gather and share samples of attacks and vulnerabilities. This shared threat intelligence is usedto develop real-time countermeasures that are automatically deployed to our customers’ firewalls.Network control and flexibilityAt the core of the NSA series is SonicOS, SonicWall’s feature-rich operating system. SonicOS provides organizations with the network control and flexibility they require through application intelligence and control, real-time visualization, an intrusion prevention system (IPS) featuring sophisticated anti-evasion technology, high-speed virtual private networking (VPN) and other robust security features.Using application intelligence and control, network administrators can identify and categorize productive applications from those that are unproductive or potentially dangerous, and control that traffic through powerful application-level policies on both a per-user and a per-group basis (along with schedules and exception lists). Business-critical applications can be prioritizedand allocated more bandwidthwhile non-essential applications arebandwidth-limited. Real-time monitoringand visualization provides a graphicalrepresentation of applications, users andbandwidth usage for granular insightinto traffic across the network.For organizations requiring advancedflexibility in their network design,SonicOS offers the tools to segmentthe network through the use of virtualLANs (VLANs). This enables networkadministrators to create a virtualLAN interface that allows for networkseparation into one or more logicalgroups. Administrators create rules thatdetermine the level of communicationwith devices on other VLANs.Built into every NSA series firewall is awireless access controller that enablesorganizations to extend the networkperimeter securely through the use ofwireless technology. Together, SonicWallfirewalls and SonicWave 802.11ac Wave2 wireless access points create a wirelessnetwork security solution that combinesindustry-leading next-generation firewalltechnology with high-speed wireless forenterprise-class network security andperformance across the wireless network.Easy deployment, setup andongoing managementLike all SonicWall firewalls, the NSAseries tightly integrates key security,connectivity and flexibility technologiesinto a single, comprehensive solution.This includes SonicWave wirelessaccess points and the SonicWall WANAcceleration Appliance (WXA) series,both of which are automatically detectedand provisioned by the managingNSA firewall. Consolidating multiplecapabilities eliminates the need topurchase and install point products thatdon’t always work well together. Thisreduces the effort it takes to deploy thesolution into the network and configureit, saving both time and money.Ongoing management and monitoringof network security are handled centrallythrough the firewall or through theSonicWall Global Management System(GMS), providing network administratorswith a single pane of glass from whichto manage all aspects of the network.Together, the simplified deploymentand setup along with the ease ofmanagement enable organizations tolower their total cost of ownership andrealize a high return on investment.SonicWallSonicWave 432iSonicWall NSA 5600The SonicWall NSA 2600 is designed to address the needs of growing small organizations, branch offices and school campuses.The SonicWall NSA 3600 is ideal for branch office and small- to medium-sized corporate environments concerned aboutthroughput capacity and performance.Dual fansPower8 x 1GbEports1GbEmanagementConsoleDualDual fansPower2 x 10GbE12 x 1GbE1GbEmanagement4 x 1GbESFP portsConsoleDualDual fansPower2 x 10GbE 12 x 1GbE1GbEmanagement 4 x 1GbESFP portsConsoleDual The SonicWall NSA 4600 secures growing medium-sizedorganizations and branch office locations with enterprise-class features and uncompromising performance.The SonicWall NSA 5600 is ideal for distributed, branch office and corporate environments needingsignificant throughput.Dual fansPower2 x 10GbE12 x 1GbE 1GbEmanagement4 x 1GbE SPF portsConsole DualNetwork Security Appliance 6600The SonicWall NSA 6600 is ideal for large distributed andcorporate central site environments requiring high throughputcapacity and performance.Dual hotswappable fansPower4 x 10GbE8 x 1GbE 1GbEmanagement 8 x 1GbE SFP ports ConsoleDualReassembly-Free Deep Packet Inspection engineThe SonicWall Reassembly-Free Deep Packet Inspection (RFDPI) is a single-pass, low latency inspection system that performs stream-based, bi-directional traffic analysis at high speed without proxying or buffering to effectivelyuncover intrusion attempts and malwaredownloads while identifying application traffic regardless of port and protocol. This proprietary engine relies onstreaming traffic payload inspection to detect threats at Layers 3-7, and takesnetwork streams through extensive andrepeated normalization and decryption in order to neutralize advanced evasion techniques that seek to confusedetection engines and sneak malicious code into the network.Once a packet undergoes thenecessary pre-processing, including SSL decryption, it is analyzedagainst a single, proprietary memory representation of three signature databases: intrusion attacks, malware and applications. The connection state is then advanced to represent the positionof the stream relative to these databases until it encounters a state of attack, or other “match” event, at which point a pre-set action is taken.In most cases, the connection is terminated and proper logging andnotification events are created. However, the engine can also be configured for inspection only or, in case of application detection, to provide Layer 7 bandwidth management services for the remainder of the application stream as soon as the application is identified.Flexible, customizable deployment options – NSA series at-a-glanceEvery SonicWall NSA firewall utilizes a breakthrough, multi-core hardware design and RFDPI for internal and external network protection without compromising network performance. NSA series NGFWs combine high-speed intrusion prevention, file and content inspection, and powerful application intelligence and control with anextensive array of advanced networking and flexible configuration features. The NSA series offers an affordable platform that is easy to deploy and manage in a wide variety of large, branch office and distributed network environments.NSA series as central-site gatewayNSA series as in-line NGFW solutionPacket Packet assembly-based processSonicWall stream-based architectureCompetitive proxy-based architecture When proxy becomes full or content too large,files bypass scanning.Reassembly-free Deep Packet Inspection (RFDPI)Reassembly-free packet scanning eliminates proxy and content size limitations.Inspection timeLessMoreInspection capacityMinMaxCapture LabsThe dedicated, in-house SonicWall Capture Labs threat research team researches and develops counter-measures to deploy to customer firewalls for up-to-date protection. The team gathers data on potential threats from several sources including our award-winning network sandboxing service, Capture Advanced Threat Protection, as well as more than 1 million SonicWall sensors located around the globe that monitor traffic for emerging threats. Itis analyzed via machine learning using SonicWall's Deep Learning Algorithmsto extract the DNA from the code to see if it is related to any known forms of malicious code.SonicWall NGFW customers benefit from continuously updated threat protection around the clock. New updates take effect immediately without reboots or interruptions. The signatures resident on the appliances are designed to protect against wide classes of attacks, covering tens of thousands of individual threats with a single signature.In addition to the countermeasureson the appliance, NSA appliances alsohave access to SonicWall CloudAV,which extends the onboard signatureintelligence with over 20 millionsignatures. This CloudAV database isaccessed by the firewall via a proprietary,light-weight protocol to augment theinspection done on the appliance. WithCapture Advanced Threat Protection,a cloud-based multi-engine sandbox,organizations can examine suspiciousfiles and code in an isolated environmentto stop advanced threats such as zero-day attacks.Advanced threat protection SonicWall Capture Advanced Threat Protection Service is a cloud-based multi-engine sandbox that extends firewall threat protection to detect and prevent zero-day threats. Suspicious files are sent to the cloud for analysis with the option to hold them at the gateway until a verdict is determined. Themulti-engine sandbox platform, which includes virtualized sandboxing, full system emulation and hypervisor level analysis technology, executes suspicious code and analyzes behavior. When afile is identified as malicious, a hash is immediately created within Capture and later a signature is sent to firewalls to prevent follow-on attacks.The service analyzes a broad rangeof operating systems and file types, including executable programs, DLL, PDFs, MS Office documents, archives, JAR and APK.Capture provides an at-a-glance threatanalysis dashboard and reports, whichdetail the analysis results for files sent tothe service, including source, destinationand a summary plus details of malwareaction once detonated.ProtectionCollectionClassificationCountermeasureL A B SGlobal management and reporting For highly regulated organizations wanting to achieve a fully coordinated security governance, compliance and risk management strategy, SonicWall Global Management System (GMS®) provides administrators a unified, secure and extensible platform to manage SonicWall firewalls, wireless access points and Dell X-Series switches through a correlated and auditable workstream process. GMS enables enterprises to easily consolidate the management of security appliances, reduce administrativeand troubleshooting complexities,and govern all operational aspects ofthe security infrastructure, includingcentralized policy management andenforcement; real-time event monitoring;user activities; application identifications;flow analytics and forensics; complianceand audit reporting; and more. GMS alsomeets the firewall’s change managementrequirements of enterprises through aworkflow automation feature. With GMSworkflow automation, all enterprises willgain agility and confidence in deployingthe right firewall policies, at the righttime and in conformance to complianceregulations. Available in software, cloudand virtual appliance options, GMSprovides a coherent way to managenetwork security by business processesand service levels, dramaticallysimplifying lifecycle management of youroverall security environments comparedto managing on a device-by-devicebasis.Port Expansion Scalability SonicWall GMS Secure Compliance EnforcementFeaturesAround-the-clock security updates New threat updates are automatically pushed to firewalls in the field with active security services, and take effectimmediately without reboots or interruptions.Bi-directional raw TCP inspection The RFDPI engine is capable of scanning raw TCP streams on any port bi-directionally preventing attacks that they tosneak by outdated security systems that focus on securing a few well-known ports.Extensive protocol support Identifies common protocols such as HTTP/S, FTP, SMTP, SMBv1/v2 and others, which do not send data in raw TCP, anddecodes payloads for malware inspection, even if they do not run on standard, well-known ports.Firewall• Stateful packet inspection• Reassembly-Free Deep PacketInspection• DDoS attack protection (UDP/ICMP/SYNflood)• IPv4/IPv6 support• Biometric authentication for remoteaccess• DNS proxy• Threat APISSL/SSH decryption and inspection1• Deep packet inspection for TLS/SSL/SSH • Inclusion/exclusion of objects, groups orhostnames• SSL ControlCapture advanced threat protection1• Cloud-based multi-engine analysis• Virtualized sandboxing• Hypervisor level analysis• Full system emulation• Broad file type examination• Automated and manual submission• Real-time threat intelligence updates • Auto-block capabilityIntrusion prevention1• Signature-based scanning• Automatic signature updates• Bidirectional inspection• Granular IPS rule capability• GeoIP enforcement• Botnet filtering with dynamic list• Regular expression matchingAnti-malware1• Stream-based malware scanning• Gateway anti-virus• Gateway anti-spyware• Bi-directional inspection• No file size limitation• Cloud malware database Application identification1• Application control• Application traffic visualization• Application component blocking• Application bandwidth management• Custom application signature creation• Data leakage prevention• Application reporting over NetFlow/IPFIX• User activity tracking (SSO)• Comprehensive application signaturedatabaseWeb content filtering1• URL filtering• Anti-proxy technology• Keyword blocking• Bandwidth manage CFSrating categories• Unified policy model with app control• Content Filtering ClientVPN• Auto-provision VPN• IPSec VPN for site-to-site connectivity• SSL VPN and IPSec client remote access• Redundant VPN gateway• Mobile Connect for iOS, Mac OSX, Windows, Chrome, Android andKindle Fire• Route-based VPN (OSPF, RIP, BGP)Networking• PortShield• Jumbo frames• IPv6• Path MTU discovery• Enhanced logging• VLAN trunking• RSTP (Rapid Spanning Tree protocol)• Port mirroring• Layer-2 QoS• Port security• Dynamic routing (RIP/OSPF/BGP)• SonicWall wireless controller• Policy-based routing (ToS/metric andECMP)• NAT• DHCP server• Bandwidth management• Link aggregation (static and dynamic)• Port redundancy• A/P high availability with state sync• A/A clustering• Inbound/outbound load balancing• L2 bridge, wire/virtual wire mode,tap mode• 3G/4G WAN failover• Asymmetric routing• Common Access Card (CAC) supportWireless• MU-MIMO• Floor plan view• Topology view• Band steering• Beamforming• AirTime fairness• MiFi extender• Guest cyclic quotaVoIP• Granular QoS control• Bandwidth management• DPI for VoIP traffic• H.323 gatekeeper and SIP proxy supportManagement and monitoring• Web GUI• Command line interface (CLI)• SNMPv2/v3• Centralized management and reporting• Logging• Netflow/IPFix exporting• Cloud-based configuration backup• BlueCoat Security Analytics Platform• Application and bandwidth visualization• IPv4 and IPv6 Management• Dell X-Series switch managementincluding cascaded switches1Requires added subscription.Testing Methodologies: Maximum performance based on RFC 2544 (for firewall). Actual performance may vary depending on network conditions and activated services.Threat Prevention/GatewayAV/Anti-Spyware/IPS throughput measured using industry standard Spirent WebAvalanche HTTP performance test and Ixia test tools. Testing done with multiple flows through multiple port pairs. Threat Prevention throughput measured with Gateway AV, Anti-Spyware, IPS and Application Control enabled.VPN throughput measured using UDP traffic at 1280 byte packet size adhering to RFC 2544. All specifications, features and availability are subject to change.For every 125,000 DPI connections reduced, the number of available DPI SSL connections increases by 750.Active/Active Clustering and Active/Active DPI with State Sync require purchase of Expanded License.Performance optimized mode can provide significant increases in performance without major impact to threat prevention efficacy.*Future use. All specifications, features and availability are subject to change.NSA series ordering information*Please consult with your local SonicWall reseller for a complete list of supported SFP and SFP+ modules© 2018 SonicWall Inc. ALL RIGHTS RESERVED. SonicWall is atrademark or registered trademark of SonicWall Inc. and/or its affiliates SonicWall, Inc.1033 McCarthy Boulevard | Milpitas, CA 95035 Regulatory model numbers:NSA 2600–1RK29-0A9NSA 3600–1RK26-0A2NSA 4600–1RK26-0A3NSA 5600–1RK26-0A4NSA 6600–1RK27-0A5About UsSonicWall has been fighting the cyber-criminal industry for over 25 years, defending small, medium size businesses and enterprises worldwide. Our combination of products and partners has enabled a real-time cyber defense solution tuned to the specific needs of the more than 500,000 businesses in over 150 countries, so you can do more business with less fear.。

计算机网络安全中的防火墙技术应用研究

计算机网络安全中的防火墙技术应用研究

通信网络技术DOI:10.19399/j.cnki.tpt.2023.02.049计算机网络安全中的防火墙技术应用研究朱俊华(玉林师范学院,广西玉林537000)摘要:防火墙是计算机网络安全保障的主要技术手段,它为计算机系统创造了一个安全可靠的运行环境,可以增强网络安全保护能力,从而提高计算机网络的稳定性,还可以在连通计算机系统内部网与外界互联网的信息通路中提供保护,过滤网络传送信号。

通过对防火墙关键技术的深入研究,全面分析防火墙技术在计算机系统安全中的应用。

关键词:计算机;网络安全;防火墙技术Application Research of Firewall Technology in Computer Network SecurityZHU Junhua(Yulin Normal University,Yulin 537000, China)Abstract: Firewall is the main technical means of computer network security, it creates a safe and reliable operating environment for the computer system, can enhance the ability of network security protection, so as to improve the stability of the computer network, can also be connected to the computer system Intranet and the Internet information path to provide protection, filtering network transmission signals. The application of firewall technology in computer system security is analyzed comprehensively through the in-depth study of the key technologies of firewall.Keywords: computer; network security; fire wall technology0 引 言随着互联网信息技术的蓬勃发展,人们的日常生活、工作和学习均离不开互联网,网络已成为人们获取信息的主要途径。

网络安全技术英语

网络安全技术英语

网络安全技术英语Network Security TechnologyIn today's digital age, network security has become more important than ever before. As we rely on digital communication and technology to connect with others, share information, and conduct business, the need to protect our networks from cyber threats has become paramount. Network security technology plays a critical role in safeguarding our networks from malicious attacks and unauthorized access.There are several types of network security technologies that can be implemented to protect a network. One of the most common types is a firewall, which monitors and controls incoming and outgoing network traffic based on predetermined security rules. Firewalls can be either hardware-based or software-based and act as a barrier between a trusted internal network and an untrusted external network, such as the Internet.Another important network security technology is virtual private network (VPN) technology. A VPN creates a secure, encrypted connection between two or more devices over the Internet. It allows users to access a network remotely while ensuring that the data transmitted between the user and the network is protected from interception and manipulation.Intrusion detection and prevention systems (IDPS) are also important network security technologies. An IDPS monitors network traffic for signs of malicious activity or unauthorized access. It can detect and alert network administrators to potentialsecurity breaches, as well as take preventive measures to stop them. An IDPS can be either network-based or host-based, depending on whether it monitors network traffic or individual hosts on a network.Network security technology also includes encryption, which is the process of converting information into an unreadable form to prevent unauthorized access. Encryption ensures the confidentiality and integrity of data transmitted over a network. Cryptographic protocols, such as secure sockets layer (SSL) and transport layer security (TLS), are commonly used to encrypt data transmitted over the Internet.In addition to these technologies, network security also involves implementing strong user authentication mechanisms, such as passwords, biometrics, and multi-factor authentication, to ensure that only authorized users can access a network. It also includes regular network vulnerability assessments and penetration testing to identify and remediate any weaknesses in the network's security. Overall, network security technology is essential for protecting our networks from cyber threats and maintaining the confidentiality, integrity, and availability of our data. It provides the necessary tools and measures to detect and prevent unauthorized access, malicious activity, and data breaches. By implementing robust network security technology, we can ensure the secure and reliable operation of our networks in an increasingly connected world.。

防火墙技术论文三篇

防火墙技术论文三篇

防火墙技术论文三篇篇一:防火墙技术毕业论文山西信息职业技术学院毕业论文()防火墙技术赵亮指导教师卫宝川学生所在系部论文提交日期论文答辩日期20 年月日论文题目:防火墙技术专业:信息管理学生:赵亮签名:指导老师卫宝川wew:wei wei 签名:摘要因特网的迅猛发展给人们的生活带来了极大的方便,但同时因特网也面临着空前的威胁。

因此,如何使用有效可行的方法使网络危险降到人们可接受的范围之内越来越受到人们的关注。

而如何实施防范策略,首先取决于当前系统的安全性。

所以对网络安全的各独立元素——防火墙、漏洞扫描、入侵检测和反病毒等进行风险评估是很有必要的。

防火墙技术作为时下比较成熟的一种网络安全技术,其安全性直接关系到用户的切身利益。

针对网络安全独立元素——防火墙技术,通过对防火墙日志文件的分析,设计相应的数学模型和软件雏形,采用打分制的方法,判断系统的安全等级,实现对目标网络的网络安全风险评估,为提高系统的安全性提供科学依据。

对网络安全的威胁主要表现在:非授权访问,冒充合法用户,破坏数据完整性,干扰系统正常运行,利用网络传播病毒,线路窃听等方面。

这以要求我们与Internet互连所带来的安全性问题予以足够重视。

计算机网络技术的飞速发展使网络安全问题日益突出,而防火墙是应用最广泛的安全产品。

本文阐述了网络防火墙的工作原理并对传统防火墙的利弊进行了对比分析,最后结合计算机科学其它领域的相关新技术,提出了新的防火墙技术,并展望了其发展前景。

【关键词】包过滤;应用层网关;分布式防火墙;检测型防火墙;嵌入式防火墙;智能防火墙;网络安全;防火墙防范策略;发展趋势Title:firewall technologyMajor:Computer Information ManagementName:Zhao Liang Signature:Supervisor:weibaochuan SignatureAbstractThe rapid development of the Internet brings great convenience to people’s life,but at the same time the Internet also is facing a n unprecedented threat.Therefore, how to use effective and feasible ways of making the network can be dangerous to the people within receiving more and more attention. And how to implement preventive strategy, first of all depends on the security of the system.So the independent network security elements -- firewall, vulnerability scanning,intrusion detection and anti-virus risk assessment is necessary.A network security firewall technology as nowadays more mature, its security is directly related to the vital interests of users. For independent network security elements -- firewall technology, through the firewall log file analysis, design of the mathematical model and prototype software, using the method of scoring system,what the system’s security leve l, to realize the network security risk assentor the target network, provides scientific basis to enhance the security of the system. The network security threats mainly displays in: unauthorized access,posing as legitimate users, damage to data integrity, interfere with the normal operation of the system, using the network to spread the virus, wiretap etc.. This requires us to safety problems brought about by the interconnection with the Internet paid enoughattention. The rapid development of computer network technology make the network security issues have become increasingly prominent, while the firewall is the most widely used security products. This paper expounds the working principle of network firewall and analyzed the advantages and disadvantages of traditional firewall, combined with new technologies related to computer science and other fields, puts forward a new firewall technology, Pandits prospect of development.【Key Words】packet filteringapplication layer gateway firewall and distributed firewall monitoring embedded firewall network intelligent firewall security firewallprevention strategiesdevelopment trend目录1 引言 (1)1.1 研究背景 (6)1.2 研究目的 (7)1.3 论文结构 (7)2 网络安全 (8)2.1 网络安全问题 (8)2.1.1 网络安全面临的主要威胁 (8)2.1.2 影响网络安全的因素 (9)2.2 网络安全措施 (9)2.2.1 完善计算机安全立法 (9)2.2.2 网络安全的关键技术 (9)2.3 制定合理的网络管理措施.................................. 10 3 防火墙概述.. (11)3.1 防火墙的概念 (11)3.1.1 传统防火墙介绍 (11)3.1.2 智能防火墙简介 (12)3.2 防火墙的功能 (13)3.2.1 防火墙的主要功能 (13)3.2.2 入侵检测功能 (13)3.2.3 虚拟专网功能 (14)3.2.4 其他功能 (14)3.3 防火墙的原理及分类 (14)3.3.1 包过滤防火墙 (15)3.3.2 应用级代理防火墙 (15)3.3.3 代理服务型防火墙 (15)3.3.4 复合型防火墙 (16)3.4 防火墙包过滤技术 (16)3.4.1 数据表结构 (16)3.4.2 传统包过滤技术 (17)3.4.3 动态包过滤 (18)3.4.4 深度包检测 (18)3.4.5 流过滤技术 (19)4 防火墙的配置.............................................................................................214.1 硬件连接与实施 (21)4.2 防火墙的特色配置 (21)4.3 软件的配置与实施........................................ 22 5 防火墙发展趋势. (24)5.1 防火墙包过滤技术发展趋势 (24)5.2 防火墙的体系结构发展趋势 (24)5.3 防火墙的系统管理发展趋势................................ 25 结论.. (25)参考文献................................................................................................................27 致谢.......................................................................................... 错误!未定义书签。

防火墙相关概念及技术介绍

防火墙相关概念及技术介绍

4、延迟:延迟是指防火墙转发数据包的延迟时间,延 迟越低,防火墙数据处理速度越快。 5、丢包率:丢包率是指在正常稳定网络状态下,应该 被转发由于缺少资源而没有被转发的数据包占全部数据 包的百分比。较低的丢包率,意味着防火墙在强大的负 载压力下,能够稳定地工作,以适应各种网络的复杂应 用和较大数据流量对处理性能的高要求。 6、平均无故障时间:平均无故障时间(MTBF)是指防火 墙连续无故障正常运行的平均时间。
ASA1000V Virtual/Cloud Firewall – Virtualization-edge ASA that runs with
Nexus1000v and a standard ASA code base – discussed but not detailed in this session
8、DHCP:内置DHCP Server 为网络中计算机动态分配IP地址;DHCP Relay的 支持能为防火墙不同端口的DHCP Server和计算机之间动态分配IP地址。
9、虚拟防火墙:在一台物理防火墙设备上提供多个逻辑上完全独立的虚拟 防火墙,每个虚拟防火墙为一个特定的用户群提供安全服务。 10、应用代理:HTTP、FTP、SMTP等协议应用代理,大多数内容过滤通过应 用代理实现。 11、流量控制:流量控制,流量优先级,带宽允许条件下的优先保障关键业 务带宽。 12、防攻击:防止各类TCP、UDP端口扫描,源路由攻击,IP碎片包攻击, DOS、DDOS攻击,蠕虫病毒以及其他网络攻击行为。
Eudemon 500
Eudemon 300 Eudemon 200S
大型企业, 运营商大型数据中心
城域网流量清洗
USG 3040 Eudemon 100E Eudemon 200 USG 50
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Network Firewall TechnologiesDavid W ChadwickIS Institute, University of Salford, Salford, M5 4WT, England Abstract. This paper provides an overview of the topic of network firewalls and theauthentication methods that they support. The reasons why a firewall is needed aregiven, plus the advantages and disadvantages of using a firewall. The components thatcomprise a firewall are introduced, along with the authentication methods that can beused by firewalls. Finally, typical firewall configurations are described, along with theadvantages and disadvantages of each configuration.1.Security Threats from connecting to the InternetMost organisations today have an internal network that interconnects their computer systems. There is usually a high degree of trust between the computer systems in the network, particularly if the network is private. However, many organizations now see the benefits of connecting to the Internet. But, the Internet is inherently an insecure network. Some of the threats inherent in the Internet include:Weak or No Authentication required. Several services e.g. rlogin, require no password to be given when a user logs in. Other services provide informationwith no or little authentication e.g. anonymous FTP, and WWW. Otherservices trust the caller at the other end to provide correct identificationinformation e.g. TCP and UDP trust the IP address of the remote station;whilst other services grant access at too large a granularity e.g. NFS grantsaccess to anyone from a particular remote host. Finally many services requirepasswords to be transmitted in the clear across the network, which make themvulnerable to capture and replay.Insecure software. Internet software, particularly shareware, free or low costpackages, often have bugs or design flaws in them usually as a result of poordesign or insufficient testing of the software. But due to their ready availability and low cost, many people still take the packages. Examples include: theUNIX sendmail program which has had numerous vulnerabilities reported in it, and a freeware FTP product which contained a Trojan Horse that allowedprivilege access to the server. Unscrupulous people are always ready toexploit these weaknesses.Sniffer programs. In 1994 the CERT reported that thousands of systems onthe Internet had been compromised by hackers, and sniffer programs installedon them. Sniffer programs monitor network traffic for usernames andpasswords, subsequently making these available to the hacker.Cracker programs. These programs, widely available on the Internet, run inbackground mode on a machine, encrypting thousands of different words andcomparing these to the encrypted passwords stored on the machine. These socalled dictionary attacks (because the words are held in a dictionary) are often very successful, providing the hacker with up to a third of the passwords on amachine.Port Scanners. These programs, again available freely from the Internet, willsend messages to all the TCP and UDP ports on a remote computer to see ifany of them are open and waiting to receive a call. Once an open port has been located, the hacker will then try to get in to the computer through it.Ease of Masquerade (Spoofing). The above make it relatively easy for thehacker to exploit the trust inherent in the Internet, or to capture passwords and replay them. Other security weaknesses include: the SMTP protocol usesASCII messages to transfer messages, so a hacker can TELNET into an SMTP port and simply type in a bogus Email message; a feature called IP sourcerouting allows a caller to falsify its IP address, and to provide the recipientwith a return path directly back to itself.So how can an organization securely connect to the Internet? One solution is to use one or more network firewalls.2.What is a Firewall ?A firewall is a secure Internet gateway that is used to interconnect a private network to the Internet (see Figure 1). There are a number of components that make up a firewall:i) the Internet access security policy of the organisation. This states, at a highlevel, what degree of security the organisation expects when connecting to the Internet. The security policy is independent of technology and techniques, andstatements from such a security policy might be: external users will not beallowed to access the corporate network without a strong level ofauthentication; any corporate information not in the public domain must betransferred across the Internet in a confidential manner, and corporate userswill only be allowed to send electronic mail to the Internet - all other serviceswill be banned.ii) the mapping of the security policy onto technical designs and proceduresthat are to be followed when connecting to the Internet. This information willbe updated as new technology is announced, and as system configurationschange etc. For example, regarding authentication, the technical design mightspecify the use of one-time passwords. Technical designs are usually based on one of two security policies, either:permit any service unless it is expressly denied, ordeny any service unless it is expressly permitted.The latter is clearly the more secure of the two.iii) the firewall system, which is the hardware and software which implementsthe firewall. Typical firewall systems comprise a IP packet filtering router, anda host computer (sometimes called a bastion host or application gateway)running application filtering and authentication software.Each of these firewall components are essential. A firewall system without an Internet access security policy cannot be correctly configured. A policy without enforced procedures is worthless as it is ignored.3.Advantages of FirewallsFirewalls have a number of advantages.They can stop incoming requests to inherently insecure services, e.g. you candisallow rlogin, or RPC services such as NFS.They can control access to other services e.g.bar callers from certain IP addresses,filter the service operations (both incoming and outgoing), e.g. stopFTP writeshide information e.g. by only allowing access to certain directories orsystemsThey are more cost effective than securing each host on the corporate network since there is often only one or a few firewall systems to concentrate on.They are more secure than securing each host due to:the complexity of the software on the host - this makes it easier forsecurity loopholes to appear. In contrast, firewalls usually havesimplified operating systems and don’t run complex applicationsoftware,the number of hosts that need to be secured (the security of the wholeis only as strong as the weakest link).4.Disadvantages of FirewallsFirewalls are not the be all and end all of network security. They do have some disadvantages, such as:They are a central point for attack, and if an intruder breaks through thefirewall they may have unlimited access to the corporate network.They may restrict legitimate users from accessing valuable services, forexample, corporate users may not be let out onto the Web, or when workingaway from home a corporate user may not have full access to theorganization’s network.They do not protect against back door attacks, and may encourage users toenter and leave via the backdoor, particularly if the service restrictions aresevere enough. Examples of backdoor entrance points to the corporatenetwork are:modems, and importing/exporting floppy discs. The security policyneeds to cover these aspects as well.They can be a bottleneck to throughput, since all connections must go via thefirewall system.Firewall systems on their own cannot protect the network against smugglingi.e. the importation or exportation of banned material through the firewall e.g.games programs as attachments to Email messages. Smuggling could still be a significant source of virus infection if users download software from externalbulletin boards etc. The recent Melissa and Love Bug viruses were smuggledinside Email messages unbeknown to the recipients. This is an area that thesecurity policy needs to address. There are software packages that can help inthis e.g. Mimesweeper runs in the firewall and will check Email attachmentsbefore letting them pass. It will remove potentially dangerous attachments orstop the Email altogether.The biggest disadvantage of a firewall is that it gives no protection against the inside attacker. Since most corporate computer crime is perpetrated by internal users, a firewall offers little protection against this threat. E.g. an employeemay not be able to Email sensitive data from the site, but they may be able tocopy it onto a floppy disc and post it.Consequently organizations need to balance the amount of time and money they spend on firewalls with that spent on other aspects of information security.5.Models, Layers and FirewallsISO uses a 7 layer model for Open Systems Interconnection, whereas the Internet can be regarded as having a 5 layer model. Whereabouts in these models are firewall systems placed?Firewall systems are usually placed at layers 3, 4 and 5 of the Internet model, (3, 4 and 7 of the ISO model), see Figure 2. Their purpose is to control access to and from a protected network. Note that a firewall can be placed between any two networks, for example between a corporate business network and its R&D network. In general, a firewall is placed between a high security domain and a lower security domain.A firewall system operating at layers 3 and 4 is sometimes called a packet filtering router or a screening router. Its purpose is to filter IP and ICMP packets andTCP/UDP ports. The router will have several ports and be able to route and filter the packets according to the filtering rules. Packet filters can also be built in software and run on dual homed PCs, but whilst these can filter packets they are not able to route them to different networks.A firewall at layer 5 Internet (7 ISO) is sometimes called a bastion host, application gateway, proxy server or guardian system. Its purpose is to filter the service provided by the application.It is also possible to operate a firewall system at Layer 2 (the link level) e.g. by configuring an Ethernet bridge to only forward certain packets, but this is not very common. The Inspection Module from Checkpoint’s Firewall 1 product operates between the link and network layers and inspects packets before letting them pass through the firewall.6.Packet Filtering RouterPacket filtering routers were the first type of firewall to be invented. A packet filtering router should be able to filter IP packets based on the following four fields:•s ource IP address•d estination IP address•T CP/UDP source port•T CP/UDP destination portFiltering is used to:•b lock connections from specific hosts or networks•b lock connections to specific hosts or networks•b lock connections to specific ports•b lock connections from specific portsWhen configuring a router, it is usually possible to specify all ports or hosts, as well as specific ones. Packet filtering routers have fast performance, since the IP packets are either forwarded or dropped without inspecting their contents (other than the address and port fields). Packet filtering routers are equivalent to guards who ask someone “where are you from and where are you going to” and if the answer is OK, the person is let into the building.For example, suppose an Internet access security policy stated that the only Internet access allowed was incoming and outgoing Email. Assuming that the organisation's Email server was located on host 123.4.5.6, then the router would be configured in the following way:Type SourceAddr DestAddr SourcePort DestPort Actiontcp *123.4.5.6 >1023 25permittcp123.4.5.6 * >1023 25permit* * * * * deny.Note. * means any address.Note. It is conventional for SMTP mail switches to always listen for incoming messages on port 25 (the well known port number), and to send messages on port numbers 1024 upwards.The first rule allows incoming Email from any address to be sent to the Email server, the second rule allows outgoing Email to be sent from the Email server to any address, whereas the last rule forbids any other traffic from passing through the router.7.Problems with Packet Filtering RoutersPacket filtering routers are a vital component of a firewall system, but they should only be considered as a first line of defence, since they do have a number of deficiencies. 1.They can be complex to configure (the rule set can be large, particularly whenmany services are supported), and there is no automatic way of checking thecorrectness of the rules i.e. that the rules correctly implement the security policy.Furthermore, if the router does not support logging of calls, there is no way of knowing if supposedly disallowed packets are actually getting through via a hole in the rules.2.If some members of staff have special requirements for Internet access, then newrules may have to be added for their machines. This further complicates the rule set, maybe making it too complex to manage. Furthermore this access is at the wrong level of granularity, since the machine rather than the user is being given permission. Users are not authenticated, only the packets are checked.3.Some basic routers do not allow TCP/UDP filtering, and this makes it impossibleto implement certain security policies e.g. the one given in the example above.4.You cannot filter between different ISO protocols running over TCP/IP. RFC1006 specifies how ISO applications such as X.500 and X.400 may run overTCP/IP. However, all of the ISO applications must connect to port 102, on which the RFC 1006 service sits.5.Finally, packet filtering routers are not very secure, since the contents of thepackets are not inspected (only their headers) so anything can be being passedthrough e.g. viruses, unauthorised delete commands etc. Finally, the senders of the packets are not authenticated.In order to overcome some of these deficiencies, more of the contents of the packets need to be inspected. This led to application level firewalls and more recently to the stateful packet inspection module from Checkpoint.8.Stateful Packet InspectionsThis is a software module that runs in the operating system of a Windows or Unix PC firewall, and inspects the packets that are arriving. The inspection is driven by security rules configured into the machine by the security officer. Headers from all seven layers of the ISO model are inspected, and information about the packets is fed into dynamic state tables that store information about the connection. The cumulative data in the tables is then used in evaluating subsequent packets on the same connection and subsequent connection attempts.Whilst this technology is more secure than simple packet filtering routers, it is not as secure as application gateways, as the full application layer data is not inspected. However, it does perform faster than application proxies. Stateful inspection is similar to a security guard that asks who are you, where are you going, and what are you carrying, before he lets you into the building.Note that this technology is patented by Checkpoint, the manufacturers of FireWall-1.9.Application Level FirewallsAn application level firewall is created by installing a (bastion) host computer running the appropriate application(s), between the packet filtering router and the intranet. The packet filtering router directs all calls from the Internet to the application level firewall.The application(s) running on the host are not usually full blown versions of the application(s), but rather are slimmed down proxy services that simply filter the messages at the application level, letting some messages through, rejecting other messages, and modifying others before accepting them.If the host does not run a particular application proxy service, then calls to this application will not usually pass through the firewall to/from the Internet. In other words, all services not running on the firewall are blocked. Common application proxies, supported by most application firewalls suppliers are FTP, SMTP, HTTP and Telnet.Application proxies are similar to a security guard who asks you why you want to enter the building and what are you carrying, and if he does not like your answer he will refuse you entry, or he may direct you to another person, or even remove some of your items or substitute them before letting you pass through. He may even take things off you before you can leave the building.FTP poses a security threat because confidential information may be exported from the organisation, or bogus information may be deposited in the organisation's file store. The FTP proxy allows FTP commands to be selectively blocked according to source and destination addresses. For example, if the organisation has information that it wishes to publish on the Internet, the proxy would forbid sending put commands (i.e. writing) to the relevant FTP server and directory. If the organisation wishes customers to send files to it, then the FTP proxy can ensure that dir and get commands are blocked, and that the FTP connection is sent to the correct system and directory. SMTP poses a security threat because mail servers (often the buggy sendmail program on UNIX systems) run with system level permissions in order to deliver incoming mail to users mailboxes. Hackers can initiate an interactive session with a mail server(by hand typing in commands or writing their own programs) and exploit its system level privileges. The SMTP proxy which runs on the firewall isolates the internal Email system from incoming Internet mail, thereby preventing Internet users from directly interfering with a mail server. Incoming mail is spooled in a reserveddirectory on the firewall host, by the proxy SMTP mail program that runs without system privileges. The remote Email sender is then disconnected before any harm can be done. Another process picks up the mail from the reserved directory and forwards it to the internal Email system.TELNET allows users to login to remote machines. This can be a security risk if remote users are allowed to login to the organisation's computers with standard username/password pairs, given the inherent weaknesses with password based systems. The Telnet proxy can be configured to state which systems can make calls to it, and which systems it will permit to be called. A typical configuration will be to allow internal users to call the Internet, but not vice versa.HTTP accesses remote web pages. HTTP proxies can filter the various HTTP commands (methods) such as POST, PUT and DELETE as well as filter the URLs (e.g. forbid connections to .com sites)In addition, all of the application proxies will provide logging of the incoming and outgoing sessions, and will authenticate the users. However, rather than each proxy having its own authentication service, it is beneficial if all proxies can make use of a common authentication module that runs on the firewall.We also want to make sure that the data being transferred is virus free, therefore we need Content Filtering as well.10.Content FilteringWith content filtering, the application data is handed over to a content filtering server that unpacks the data to see what is inside, and harmful content is then disposed of. For example, zipped files are unzipped first to see what is inside them. If the content contains a virus it will be discarded or disinfected. (Note, this requires that organisations regularly update their virus checking software, as new viruses are found daily.) File types are identified (not from the filename extension but from their content) and undesirable types e.g. executables can be removed, according to the security policy. Alternatively, if imported code is digitally signed, the author/signer can be checked to see if he is on a trusted list of signers and then the file can be accepted. Text files can be scanned for a list of undesirable key words (e.g. swear words or explicit sexual language). Finally, incoming http Java or ActiveX applets can be removed if this is company policy. Content filtering is like the security guard that empties your pockets, and gives you a full body check both on entering and leaving a building.The biggest vendor of content checking software is Checkpoint with its MIMEsweeper family of products (that include MAILsweeper and WEBsweeper).The biggest problem with scanning and filtering all the packet contents as they pass through the firewall, is the amount of processing time this takes, see Figure 3. Consequently, large servers are needed if all incoming data is to be screened.11.AuthenticationIt has already been noted that simple passwords can not be relied upon to provide authentication information over the Internet. Something stronger is needed. The logical place to site the strong authentication functionality is in the firewall. An increasingly common authentication method is the use of one-time passwords or hashed passwords. But digital signatures are also becoming more popular as PKIs get implemented. Digital signatures rely on asymmetric encryption. The sender digitally signs a message, by appending to it a digital summary of the message (called a message digest), encrypted with his private key. The firewall can decipher the digital signature using the sender’s public key. The firewall can also compute the message digest and compare this to the deciphered one. If both digests are the same, the message is authentic (it must have come from the owner of the private key and it has not been tampered with during transfer).SOCKS authentication was one of the first general authentication mechanisms to be placed in a firewall, that allows remote applications to authenticate to the firewall. RADIUS is the Internet draft standard for dial in user authentication to a firewall.11.1.SOCKS AuthenticationSOCKS provides an authentication layer for the firewall that can be used by all application proxies. Calls come into the SOCKS service, are authenticated by it, then a call is opened up to the application proxy which does further application level filtering before making a call to the application on the intranet, see Figure 4.SOCKSv5 operates as follows. A TCP client opens up a connection to a SOCKS server at port 1080 in the firewall. The client negotiates an authentication method, then authenticates to the SOCKS server. If successful, the client sends a Relay Request to the SOCKS server. The SOCKS server then either relays the request to the requested server or rejects the request. If accepted, thereafter messages between the application server and the client are relayed via the SOCKS server. A full description of SOCKSv5 can be found in [1].A disadvantage of SOCKSv5 is that it requires modified TCP software in the client system. Fortunately this is now widely implemented, and is supported for example in Netscape and Internet Explorer, plus freely available implementations of the SOCKS library and server are available for download from the Internet.Authentication methods primarily supported by SOCKS are username password and GSS-API. But this is not such a wide range, and the password is sent in the clear so it is open to sniffing attacks.11.2.RADIUSThe Remote Authentication Dial In User Service (RADIUS) is specified in RFC 2865 [2]. The mode of operation is as follows:1.The user dials into the network via a modem. The network can be the corporatenetwork running its own modems, or it could be an Internet Service Provider.2.The receiving computer acts as a RADIUS client, and will usually ask the user forhis username and password.3.The RADIUS client sends an Access Request message to the RADIUS serverincluding the username and password (which is encoded using MD5 to stopsniffing -see later).Therefore the password attribute can be blank or set to a fixed string such as “challenge required”.All messages are sent using UDP, and the RADIUS well known port number is 1812. The advantages of RADIUS are that it is an open protocol, an Internet Draft Standard, supports a wide range of authentication mechanisms, is widely supported by vendors, and is extensible. RADIUS protocol messages contain a series of attributes (type, length, value tuples). These are standardised and registered with the ICANN (formerly IANA), and new attributes can be added as the Internet community agree on a need for them. Already defined attributes include: user’s name, user’s password, RADIUS client’s IP address, call-back number (for modem’s which call the user back at home) etc.11.3.Hardware Based One Time PasswordsAn increasingly common authentication method is the use of one-time passwords. There are two popular variants of one-time passwords, one is based on a challenge response mechanism, the other on synchronised clocks.With the challenge response mechanism, the user logs into the firewall, and the firewall passes the user a challenge, usually in the form of a numeric string. The user responds to the challenge with a one-time password that is computed from the string by his hardware/software according to a pre-defined encryption algorithm that is also known to the firewall (see Figure 7). One such system (SecureNet from Digital Pathways) relies on the user having a one-time password card the size of a credit card that is capable of computing the passwords. The card has a digital display, and requires a PIN number to be entered before it can be used. Another system (S/key from Bellcore) relies on software in the remote user’s PC to compute the password (see next section).With the clock synchronised mechanism (e.g. SecureID from RSA Security), both the card and the firewall authentication system compute a new password every 60 seconds, according to a pre-defined encryption algorithm which uses the date and time, and a shared secret. This eliminates the need for a challenge string (see Figure 7). With the SecureID system, the user must transfer a PIN number plus the computed password, so that if the card is stolen it cannot be used by anyone else. This mechanism is sometimes referred to as Two Factor Authentication, as it is based on something I possess (the card) and something I know (the PIN).11.4.Software Based One Time Passwords - S/KeyS/Key is a challenge-response one time password mechanism, and is widely supported by firewall vendors. Free S/Key implementations are available from the Internet. S/Key works as follows.The server hashes up the user’s password plus a random seed word a large number of times (say a thousand times) and stores the resulting 128 bit number. When the user asks to log in, the server returns a challenge comprising the seed word and the number 999 (one less than the n th hash stored). The user is asked for his password, then his PC computes a hash of the password and seed word, then repeats this another 998 times and sends the resulting 128 bit hash to the server. This number is usually sent as ASCII words rather than binary, to stop the eight bit of each byte possibly being corrupted during transfer. The server takes the incoming number, hashes it once and compares it with its stored value. If they are the same it knows the user is authentic and allows the login. It then stores the hash it has been given. The next time the user wants to login, the server returns the seed word and the number 998, and the whole process is repeated. The user can login another 997 times until number 1 is reached. The server then has to invent a new random seed word and hash this with the password a thousand times and store it. The whole process then starts again.。

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