如要將a.com重定向到www.a.com，則配置web.config如下：

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <system.webServer>
        <rewrite>
  &nbsp;&nbsp;        <rules>
    ;            <rule name="www" stopProcessing="true">
                &nbsp;   <match url=".*" />
       &nbsp;            <conditions>
           &nbsp;            <add input="{HTTP_HOST}" pattern="^a\.com$" />
        ;            </conditions>
       &nbsp;     ;       <action type="Redirect" url="//www.a.com/{R:0}" redirectType="Permanent" />
          &nbsp;     </rule>
         &nbsp;  </rules>
        </rewrite>
   &nbsp;</system.webServer> 
</configuration>