PPP协议是数据链路层的一个协议，它被广泛用于接入Internet中。PPP协议是一个(53)。帧长为整数个字节。它克服了SLIP协议的缺点，可以进行协商，并且(54)。它可以分成3个层次，其中的网络层协议被称为(55)，包括了不同的网络层协议。利用PPP的优势，结合以太网产生了(56)协议，该协议可以通过简单的共享设备将多个客户网段接入到骨干网。若通过SLIP方式接入Internet，用户端p是(57)。

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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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