ICMP是Internet控制协议报文协议，它允许主机或路由器报告(37)和提供有关异常情况的报告。它是(38)的组成部分，其报文格式包括报文头和数据区两部分，其中报文头部分是由—些刨等三个字段组成，字段长度分别为(40)。ICMP可作为询问报文，用来测试目的站是否可达，以及了解其有关状态，常用(41)命令来进行这种测试。

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Pharming is a scamming practice in which malicious code is installed on a personal computer or server, misdirecting users to(71)fraudulent Web sites without their knowledge or consent. Pharming has been called "phishing without a lure".

 In phishing, the perpetrator sends out legitimate-(72)looking e-malls, appearing to come from some of the Web's most popular sites, in an effort to obtain personal and financial information from individual recipients. But in pharming, larger numbers of computer users can be(73)victimized because it is not necessary to target individuals one by one and no conscious action is required on the part of the victim. In one form. of pharming attack, code sent in an e-mail modifies local host files on a personal computer. The host files convert URLs into the number strings that the computer uses to access Web sites. A computer with a compromised host file will go to the fake Web site even if a user types in the correct Internet address or clicks on an affected(74)bookmark entry. Some spyware removal programs can correct the corruption, but it frequently recurs unless the user changes browsing.(75)habits.

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