Win7系统电脑hosts文件详解

　　一、什么是hosts文件？

　　hosts是一个没有扩展名的系统文件，其基本作用就是将一些常用的网址域名与其对应的IP地址建立一个关联“数据库”，

　　当用户在浏览器中输入一个需要登录的网址时，系统会首先自动从Hosts文件中寻找对应的IP地址，一旦找到，系统会立即打开对应网页，如果没有找到，则系统再会将网址提交DNS域名解析服务器进行IP地址的解析，如果发现是被屏蔽的IP或域名，就会禁止打开此网页！

　　二、Win7的hosts 默认文件

　　文件地址：C：\WINDOWS\system32\drivers\etc\hosts

　　默认里面的内容如下：

　　# Copyright (c) 1993-2009 Microsoft Corp.

　　#

　　# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.

　　#

　　# This file contains the mappings of IP addresses to host names. Each

　　# entry should be kept on an individual line. The IP address should

　　# be placed in the first column followed by the corresponding host name.

　　# The IP address and the host name should be separated by at least one

　　# space.

　　#

　　# Additionally， comments (such as these) may be inserted on individual

　　# lines or following the machine name denoted by a ‘#’ symbol.

　　#

　　# For example：

　　#

　　# 102.54.94.97 rhino.acme.com # source server

　　# 38.25.63.10 x.acme.com # x client host

　　# localhost name resolution is handled within DNS itself.

　　# 127.0.0.1 localhost

　　# ：：1 localhost