● Melissa and LoveLetter made use of the trust that exists between friends or colleagues. Imagine receiving an （71 ） from a friend who asks you to open it. This is what happens with Melissa and several other similar email （72） . Upon running, such worms usually proceed to send themselves out to email addresses from the victim's address book, previous emails, web pages  （73） .As administrators seek to block dangerous email attachments through the recognition of well-known （74） , virus writers use other extensions to circumvent such protection. Executable （.exe） files are renamed to .bat and .cmd plus a whole list of other extensions and will still run and successfully infect target users.Frequently, hackers try to penetrate networks by sending an attachment that looks like a flash movie, which, while displaying some cute animation, simultaneously runs commands in the background to steal your passwords and give the  （75） access to your network.

试卷相关题目

• 1● DOM is a platform- and language- （66） API that allows programs and scripts to dynamically access and update the content, structure and style of WWW documents（currently, definitions for HTML and XML documents are part of the specification）. The document can be further processed and the results of that processing can be incorporated back into the presented  （67） . DOM is a  （68） -based AP1 to documents, which requires the whole document to be represented in  （69）  while processing it. A simpler alternative to DOM is the event-based SAX, which can be used to process very large （70） documents that do not fit into the memory available for processing.

  A.specific

  B.neutral

  C.contained

  D.related

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• 2● 在以下网络应用中，要求带宽最高的应用是 （65） 。

  A.可视电话

  B.数字电视

  C.拨号上网

  D.收发邮件

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• 3● 在TCP／IP网络中，为各种公共服务保留的端口号范围是 （64） 。

  A.1~255

  B.1~1023

  C.1~1024

  D.1~65535

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• 4● 以下选项中，可以用于Internet信息服务器远程管理的是 （63） 。

  A.Telnet

  B.RAS

  C.FTP

  D.SMTP

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• 5● 一个局域网中某台主机的IP地址为176.68.160.12，使用22位作为网络地址，那么该局域网的子网掩码为 （61） ，最多可以连接的主机数为 （62） 。

  A.255.255.255.0

  B.255.255.248.0

  C.255.255.252.0

  D.255.255.0.0

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