1、 专业外文翻译 题 目 Internet Security 系 （院） 计算机科学技术系 专 业 通信工程 班 级 2008 级 2 班 学生姓名 李华山 学 号 2008110311 指导教师 陈瑞斌 职 称 讲师 二 一 二 年 五 月 二十 日 滨州学院毕业设计 (专业外文翻译 ) 1 Internet Security An intruder with the right background and malicious intent has many ways to infiltrate internal company systems and network devices thr
2、ough the Internet connection. Once inside, the hacker has free reign to destroy, change, or steal data and these actions because various sorts of network havoc. The most popular use of the Internet, e-mail, is also insecure. The same hacker with a protocol analyzer and access to routers and other ne
3、twork devices can intercept or change messages. Threats like these confront such industries as Internet commerce and corporations that wish to interconnect their offices through LA Ns via the Internet. The network security market is quickly responding to the threats by applying authentication and en
4、cryption technologies to the Internet and by developing new products. These products come at a time where methods of attacking user networks are more elaborate and vendors are improving their products to keep up with the increased threats. “Users need these tools because they realize they cant use t
5、raditional monitoring tools to stop increasingly sophisticated attacks,” says Jim Hurley, an analyst with The Aberdeen Group. This article describes various security threats and solutions needed to protect individuals and companies. Types of Internet Security Protection 1. Security Policy Internet c
6、onnections will never be 100 percent secure. Rather than aiming for total security, an organization has to assess the value of the information it is trying to protect and balance that against the likelihood of a security violation and the cost of implementing various security measures. A companys fi
7、rst line-of-defense should be either to devise or to revise its security policy for the organization that takes Internet connections into account. This policy should define in detail which employees have rights to specific services. It should also educate employees about their responsibilities for p
8、rotecting the organizations information, such as protecting passwords, and clearly spell out actions that will be taken if a security violation is detected. Such a policy can be the first step, explaining to employees where the company stands on misuse of Internet 滨州学院毕业设计 (专业外文翻译 ) 2 connections. P
9、art of the process will require evaluating the cost to the company of different types of security violations. Corporations will want to involve people at the highest levels of the organization in this process. Hiring a computer security consultant may be of some help. Once a companywide policy is im
10、plemented, the company then should start evaluating the use of firewalls, encryption, and authentication. 2. Firewall A firewall is a barrier between two networks, an internal network (trusted network) and an external network (untrusted network). Here the external network is the Internet. Firewalls
11、examine incoming and outgoing packets and according to a set of rules defined by the administrator, either let them through or block them out. Firewalls are not an Internet security remedy, but they are essential to the strategy. Different kinds of firewalls function differently. They scrutinize, ex
12、amine, and control the network traffic in numerous ways depending on their software architecture. Below are firewalls that work in different ways. 1） Packet Filtering Firewall Technique Many routers use a firewall technique called packet filtering, which examines the source and destination addresses
13、 and ports of incoming TCP and UDP packets, denying or allowing packets to enter based on a set of predefined rules set by the administrator. Packet filters are inexpensive, transparent to users, and have a negligible impact on network performance. Configuring packet filtering is a relatively comple
14、x process, requiring a precise knowledge of network, transport, and even application protocol strategy. A problem with packet filters is that they are susceptible to“IP spoofing”, a trick that hackers use to gain access to a corporate network. Intruders fool the firewall by changing Internet Protocol addresses in packet headers to ones that are acceptable. 2） The Application-Gateway Firewall A more sophisticated and secure type of firewall is an application gateway, which is generally considered more secure than packet filters. Application gateways are programs
