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这是很好的学习嵌入式LINUX的文章

class="HOSTID">fe80::200:21ff:fe03:8e1%rl0</tt>是一个自动配置的链路环回地址。它作为自动配置的一部分由MAC生成。</p>

<p>关于IPv6地址的结构的更多信息，请参看<a href="http://www.ietf.org/rfc/rfc3513.txt"
target="_top">RFC3513</a>。</p>
</div>

<div class="SECT2">
<h2 class="SECT2"><a id="AEN37568" name="AEN37568">24.10.3. 进行连接</a></h2>

<p>目前，有四种方式可以连接到其它IPv6主机和网络：</p>

<ul>
<li>
<p>加入试验性的6bone(骨干)</p>
</li>

<li>
<p>从你的上一级提供商那里获得IPv6网络。与你的互联网提供商讨论以求指导。</p>
</li>

<li>
<p>使用 6-to-4 通道 (<a href="http://www.ietf.org/rfc/rfc3068.txt"
target="_top">RFC3068</a>)</p>
</li>

<li>
<p>如果你是括号连接(dial-up connection)，请使用<a
href="http://www.FreeBSD.org/cgi/url.cgi?ports/net/freenet6/pkg-descr"><tt
class="FILENAME">net/freenet6</tt></a> port。</p>
</li>
</ul>

<p>这里我们就讨论如何连接到6bone，因为它目前看来是最流行的一种方式。</p>

<p>首先看一下<a href="http://www.6bone.net/"
target="_top">6bone</a>网站，并找出离你最近的6bone连接。给某位值得信赖的人写信过去，如果运气好，你就会得到关于如何设置你的连接的指导。通常这包括了设置GRE
(gif) 通道。</p>

<p>这里有一个典型的关于设置<span class="CITEREFENTRY"><span
class="REFENTRYTITLE">gif</span>(4)</span>通道的例子。</p>

<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">ifconfig gif0 create</kbd> <samp
class="PROMPT">#</samp> <kbd
class="USERINPUT">ifconfig gif0</kbd> gif0: flags=8010&lt;POINTOPOINT,MULTICAST&#62; mtu 1280 <samp
 class="PROMPT">#</samp> <kbd class="USERINPUT">ifconfig gif0 tunnel <var
class="REPLACEABLE">MY_IPv4_ADDR</var>  <var
class="REPLACEABLE">HIS_IPv4_ADDR</var></kbd> <samp class="PROMPT">#</samp> <kbd
class="USERINPUT">ifconfig gif0 inet6 alias <var
class="REPLACEABLE">MY_ASSIGNED_IPv6_TUNNEL_ENDPOINT_ADDR</var></kbd>
</pre>

<p>把大写字母换成你从上一级6bone节点收到的信息。</p>

<p>这样就建立了通道。通过<span class="CITEREFENTRY"><span
class="REFENTRYTITLE">ping6</span>(8)</span> <tt
class="HOSTID">ff02::1%gif0</tt>，检查通道是否工作。你应该会收到两个ping回应。</p>

<div class="NOTE">
<blockquote class="NOTE">
<p><b>注:</b> 或许你会对地址<tt
class="HOSTID">ff02:1%gif0</tt>感上兴趣，它是一个multicast地址。<var
class="LITERAL">%gif0</var>表明在网络接口<tt
class="DEVICENAME">gif0</tt>上的multicast地址已经用上了。因为我们<tt
class="COMMAND">ping</tt>一个multicast地址的时候，通道的另一端也应该会回应。</p>
</blockquote>
</div>

<p>到现在，设置一个到6bone上级连接的路由应该是相当简单了。</p>

<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">route add -inet6 default -interface gif0</kbd> <samp
class="PROMPT">#</samp> <kbd class="USERINPUT">ping6 -n <var
class="REPLACEABLE">MY_UPLINK</var></kbd>
</pre>

<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">traceroute6 www.jp.FreeBSD.org</kbd> (3ffe:505:2008:1:2a0:24ff:fe57:e561) from 3ffe:8060:100::40:2, 30 hops max, 12 byte packets 1  atnet-meta6  14.147 ms  15.499 ms  24.319 ms 2  6bone-gw2-ATNET-NT.ipv6.tilab.com  103.408 ms  95.072 ms * 3  3ffe:1831:0:ffff::4  138.645 ms  134.437 ms  144.257 ms 4  3ffe:1810:0:6:290:27ff:fe79:7677  282.975 ms  278.666 ms  292.811 ms 5  3ffe:1800:0:ff00::4  400.131 ms  396.324 ms  394.769 ms 6  3ffe:1800:0:3:290:27ff:fe14:cdee  394.712 ms  397.19 ms  394.102 ms
</pre>

<p>这个输出可能随机器而不同。到现在，你应该可以到达 IPv6 站点<a
href="http://www.kame.net" target="_top">www.kame.net</a>，并看到那只正跳舞的乌龟 --
如果你有一个支持IPv6的浏览器，如<a
href="http://www.FreeBSD.org/cgi/url.cgi?ports/www/mozilla/pkg-descr"><tt
class="FILENAME">www/mozilla</tt></a>， <b class="APPLICATION">Konqueror</b>（<a
href="http://www.FreeBSD.org/cgi/url.cgi?ports/x11/kdebase3/pkg-descr"><tt
class="FILENAME">x11/kdebase3</tt></a>的一部分）或<a
href="http://www.FreeBSD.org/cgi/url.cgi?ports/www/epiphany/pkg-descr"><tt
class="FILENAME">www/epiphany</tt></a>。</p>
</div>

<div class="SECT2">
<h2 class="SECT2"><a id="AEN37629" name="AEN37629">24.10.4. IPv6世界里的DNS</a></h2>

<p>对于IPv6有两种类型的DNS记录：IETF已经宣布A6是过时标准；现行的标准是AAAA记录。</p>

<p>
使用AAAA记录是很简单的。通过增加下面内容，给你的主机分配置你刚才接收到的新的IPv6地址：</p>

<pre class="PROGRAMLISTING">
MYHOSTNAME           AAAA    MYIPv6ADDR
</pre>

<p>到你的主域DNS文件里，就可以完成。要是你自已没有<acronym
class="ACRONYM">DNS</acronym>域服务，你可以询问你的<acronym
class="ACRONYM">DNS</acronym>提供商。目前的<b class="APPLICATION">bind</b>版本(version
8.3 与 9)和<a href="http://www.FreeBSD.org/cgi/url.cgi?ports/dns/djbdns/pkg-descr"><tt
class="FILENAME">dns/djbdns</tt></a>（含IPv6补丁）支持AAAA记录。</p>
</div>

<div class="SECT2">
<h2 class="SECT2"><a id="AEN37639" name="AEN37639">24.10.5. Applying the needed changes
to <tt class="FILENAME">/etc/rc.conf</tt></a></h2>

<div class="SECT3">
<h3 class="SECT3"><a id="AEN37642" name="AEN37642">24.10.5.1. IPv6 Client
Settings</a></h3>

<p>These settings will help you configure a machine that will be on your LAN and act as a
client, not a router. To have <span class="CITEREFENTRY"><span
class="REFENTRYTITLE">rtsol</span>(8)</span> autoconfigure your interface on boot all you
need to add is:</p>

<pre class="PROGRAMLISTING">
ipv6_enable="YES"
</pre>

<p>To statically assign an IP address such as <tt
class="HOSTID">2001:471:1f11:251:290:27ff:fee0:2093</tt>, to your <tt
class="DEVICENAME">fxp0</tt> interface, add:</p>

<pre class="PROGRAMLISTING">
ipv6_ifconfig_fxp0="2001:471:1f11:251:290:27ff:fee0:2093"
</pre>

<p>To assign a default router of <tt class="HOSTID">2001:471:1f11:251::1</tt> add the
following to <tt class="FILENAME">/etc/rc.conf</tt>:</p>

<pre class="PROGRAMLISTING">
ipv6_defaultrouter="2001:471:1f11:251::1"
</pre>
</div>

<div class="SECT3">
<h3 class="SECT3"><a id="AEN37657" name="AEN37657">24.10.5.2. IPv6 Router/Gateway
Settings</a></h3>

<p>This will help you take the directions that your tunnel provider, such as the <a
href="http://www.6bone.net/" target="_top">6bone</a>, has given you and convert it into
settings that will persist through reboots. To restore your tunnel on startup use
something like the following in <tt class="FILENAME">/etc/rc.conf</tt>:</p>

<p>List the Generic Tunneling interfaces that will be configured, for example <tt
class="DEVICENAME">gif0</tt>:</p>

<pre class="PROGRAMLISTING">
gif_interfaces="gif0"
</pre>

<p>To configure the interface with a local endpoint of <var
class="REPLACEABLE">MY_IPv4_ADDR</var> to a remote endpoint of <var
class="REPLACEABLE">REMOTE_IPv4_ADDR</var>:</p>

<pre class="PROGRAMLISTING">
gif_config_gif0="<var class="REPLACEABLE">MY_IPv4_ADDR REMOTE_IPv4_ADDR</var>"
</pre>

<p>To apply the IPv6 address you have been assigned for use as your IPv6 tunnel endpoint,
add:</p>

<pre class="PROGRAMLISTING">
ipv6_ifconfig_gif0="<var class="REPLACEABLE">MY_ASSIGNED_IPv6_TUNNEL_ENDPOINT_ADDR</var>"
</pre>

<p>Then all you have to do is set the default route for IPv6. This is the other side of
the IPv6 tunnel:</p>

<pre class="PROGRAMLISTING">
ipv6_defaultrouter="<var class="REPLACEABLE">MY_IPv6_REMOTE_TUNNEL_ENDPOINT_ADDR</var>"
</pre>
</div>
</div>

<div class="SECT2">
<h2 class="SECT2"><a id="AEN37676" name="AEN37676">24.10.6. Router Advertisement and Host
Auto Configuration</a></h2>

<p>This section will help you setup <span class="CITEREFENTRY"><span
class="REFENTRYTITLE">rtadvd</span>(8)</span> to advertise the IPv6 default route.</p>

<p>To enable <span class="CITEREFENTRY"><span
class="REFENTRYTITLE">rtadvd</span>(8)</span> you will need the following in your <tt
class="FILENAME">/etc/rc.conf</tt>:</p>

<pre class="PROGRAMLISTING">
rtadvd_enable="YES"
</pre>

<p>It is important that you specify the interface on which to do IPv6 router
solicitation. For example to tell <span class="CITEREFENTRY"><span
class="REFENTRYTITLE">rtadvd</span>(8)</span> to use <tt
class="DEVICENAME">fxp0</tt>:</p>

<pre class="PROGRAMLISTING">
rtadvd_interfaces="fxp0"
</pre>

<p>Now we must create the configuration file, <tt class="FILENAME">/etc/rtadvd.conf</tt>.
Here is an example:</p>

<pre class="PROGRAMLISTING">
fxp0:\
    :addrs#1:addr="2001:471:1f11:246::":prefixlen#64:tc=ether:
</pre>

<p>Replace <tt class="DEVICENAME">fxp0</tt> with the interface you are going to be
using.</p>

<p>Next, replace <tt class="HOSTID">2001:471:1f11:246::</tt> with the prefix of your
allocation.</p>

<p>If you are dedicated a <tt class="HOSTID">/64</tt> subnet you will not need to change
anything else. Otherwise, you will need to change the <var
class="LITERAL">prefixlen#</var> to the correct value.</p>
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