<?xml version="1.0" encoding="utf-8"?>
<page xmlns="http://projectmallard.org/1.0/" xmlns:its="http://www.w3.org/2005/11/its" type="topic" style="task" id="net-firewall-on-off" xml:lang="zh-CN">

  <info>
    <link type="guide" xref="net-security" group="#first"/>

    <revision pkgversion="3.4.0" date="2012-02-20" status="final"/>
    <revision pkgversion="3.10" date="2013-11-03" status="incomplete"/>
    <revision pkgversion="3.18" date="2015-09-28" status="final"/>

    <credit type="author">
      <name>Paul W. Frields</name>
      <email>stickster@gmail.com</email>
    </credit>

    <include xmlns="http://www.w3.org/2001/XInclude" href="legal.xml"/>

    <desc>您可以控制哪些程序可以访问网络，这有助于保持您的计算机安全。</desc>
  
    <mal:credit xmlns:mal="http://projectmallard.org/1.0/" type="translator copyright">
      <mal:name>TeliuTe</mal:name>
      <mal:email>teliute@163.com</mal:email>
      <mal:years>2011, 2012</mal:years>
    </mal:credit>
  </info>

  <title>启用和阻止防火墙访问</title>

  <p>您的系统可能安装有<em>防火墙</em> ，可以阻止来自其他网络用户的程序操作。这有助于保持您的计算机安全。</p>

  <p>许多应用程序可以使用网络连接，当连接到互联网后，您可以共享文件或允许其他人远程查看您的桌面，这取决于您的计算机设置，您可能需要调整防火墙来实现预期的网络服务。</p>

  <p>Each program that provides network services uses a specific <em>network
  port</em>. To enable other computers on the network to access a service, you
  may need to “open” its assigned port on the firewall:</p>


  <steps>
    <item>
      <p>Go to <gui>Activities</gui> in the top left corner of the screen and
      start your firewall application. You may need to install a firewall
      manager yourself if you can’t find one (for example, Firestarter or
      GUFW).</p>
    </item>
    <item>
      <p>开启或禁用网络服务端口，取决于您是否想让其他人访问，需要设置哪一个端<link xref="net-firewall-ports">取决于运行的服务</link>。</p>
    </item>
    <item>
      <p>保存和应用更改，还可以参考防火墙工具的其他指导。</p>
    </item>
  </steps>

</page>