问题 问答题


阅读以下关于校园网方面的叙述,回答问题1,问题2和问题3。
校园是孕育Internet 最早的发源地之一,Internet 从校园开始,迅速覆盖了全球。而校园始终是互联网最新技术的发源地。目前,我国的大专院校普遍建成了校园网,中小学的网络建设也在快速发展之中。而当前,互联网面临的最大问题就是安全性,校园网不可避免地面临同样的挑战。而校园网络覆盖广阔,应用众多和其开放的架构,使校园网面临的安全问题更具多样性,也更严峻。
校园网的特点:①开放性:任何应用均可运行在校园网这上,没有严格的应用限制和要求。 P2P,实时通信等等应用都在校园网上广泛使用。②各种应用可能存在的安全隐患各自不同,大量的应用必将导致大量安全隐患的存在。需要更多的工作量,降低和消除安全隐患和漏洞。③数据存放的分布性:校园网内,各种科研成果、论文、教案、教材、成绩、资料等等对入侵者非常有吸引力的数据资料均以非常公开的形式存放在校园网络的各个服务器,甚至个人PC之上。④非集中的存放方式,使保护和防御的边界模糊不清。新的资料和成果的价值无法评估,导致不可能采用简单的分级保护。⑤服务器众多:校园网内的服务器数量多,分布广,提供的各种应用服务种类齐全,内容丰富。⑥服务器提供的服务多,数量多。存在的安全漏洞和隐患相应较多,也容易被利用为攻击体跳板。⑦网络覆盖广泛:中国教育网 CERNET覆盖广泛,目前已经覆盖了全国主要的高等院校,很多校园网又有自己的互联网连接。所以校园网不是一个孤立的网络,而是与国际互联网紧密连接的园区网络。⑧可能的安全入侵,病毒传播来源自国际互联网,安全隐患和攻击众多,校园网始终是攻击者首选目标之一。⑨使用者众多;校园网的使用者流动性非常大,学生换届、访问学者、交流学生都经常引起使用者群体的流动和改变。

[问题1]
考虑到一般高校或教育局下属单位的内部服务器及用户是其系统中最为关键的防护对象,并且有独立的Internet出口,所以都容易受到来自外部的攻击,而且学校网络中邮件服务器很多采用的是自行开发的系统。根据以上校园网的特点用100字分析为解决校园网的安全问题所设计的系统应结合于应用程序还是协议,为什么

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解析:所设计的系统应与应用程序无关,只与协议有关,符合学校网络的网络安全需求,能够对HTFP、 FTP、SMTP、POP3、IMAP和NetBios等协议的内容进行过滤,这样内部的用户无论访问Internet,还是访问教育行业内部、外部的邮件服务器以及WEB服务器都可以得到全面的安全防护。

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In 1880, Sir Joshua Waddilove, a Victorian philanthropist, founded Provident Financial to provide affordable loans to working-class families in and around Bradford, in northern England. This month his company, now one of Britain’s leading providers of "home credit"— small, short-term, unsecured loans—began the nationwide rollout of Vanquis, a credit card aimed at people that mainstream lenders shun. The card offers up to £ 200 ($ 380) of credit, at a price: for the riskiest customers, the annual interest rate will be 69%.

Provident says that the typical interest rate is closer to 50% and that it charges no fees for late payments or breaching credit limits. Still, that is triple the rate on regular credit cards and far above the 30% charged by store cards. And the Vanquis card is being launched just when Britain’s politicians and media are full of worry about soaring consumer debt. Last month, a man took his own life after running up debts of £ 130000 on 22 different credit cards.

Credit cards for "sub-prime" borrowers, as the industry delicately calls those with poor credit records, are new in Britain but have been common in America for a while. Lenders began issuing them when the prime market became saturated, prompting them to look for new sources of profit. Even in America, the sub-prime market has plenty of room for growth. David Robertson of the Nilson Report, a trade magazine, reckons that outstanding sub-prime credit-card debt accounts for only 3% of the $ 597 billion that Americans owe on plastic. The sub-prime sector grew by 7.9% last year, compared with only 2.6% for the industry as a whole.

You might wonder, though, how companies can make money from lending to customers they know to be bad risks—or at any rate, how they can do it legitimately. Whereas delinquencies in the credit-card industry as a whole are around 4%-5% , those in the sub-prime market are almost twice as high, and can reach 15% in hard times.

Obviously, issuers charge higher interest rates to compensate them for the higher risk of not being repaid. And all across the credit-card industry, the assessment and pricing of risks has been getting more and more refined, thanks largely to advances in technology and data processing. Companies also use sophisticated computer programs to track slower payment or other signs of increased risk. Sub-prime issuers pay as much attention to collecting debt as to managing risk; they impose extra charges, such as application fees; and they cap their potential losses by lending only small amounts ($ 500 is a typical credit limit).

All this is easier to describe than to do, especially when the economy slows. After the bursting of the technology bubble in 2000, several sub-prime credit-card providers failed. Now there are only around 100, of which nine issue credit cards. Survivors such as Metris and Providian, two of the bigger sub-prime card companies, have become choosier about their customers’ credit histories.

As the economy recovered, so did lenders’ fortunes. Fitch, a rating agency, says that the proportion of sub-prime credit-card borrowers who are more than 60 days in arrears (a good predictor of eventual default) is the lowest since November 2001. But with American interest rates rising again, some worry about another squeeze. As Fitch’s Michael Dean points out, sub-prime borrowers tend to have not just higher-rate credit cards, but dearer auto loans and variable-rate mortgages as well. That makes a risky business even riskier.

It can be inferred from the passage that()

A. the failure of credit card providers is caused by the bursting of technology bubble

B. the politicians and the media play a negative part in promoting credit industry

C. higher national interest rate increases sub-prime lenders’ risks of not being repaid

D. credit industry has a better chance of development when the economy slows down