Add a section about static route configuration (this addition contains
an ASCII art diagram, I'll add a graphic version ASAP). PR: docs/63310 Submitted by: Al Hoang <hoanga@mac.com>
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Marc Fonvieille
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2020-12-08 03:00:23 +00:00
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@ -455,6 +455,133 @@ host2.example.com link#1 UC 0 0
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however.</para>
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</sect2>
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<sect2>
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<sect2info>
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<authorgroup>
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<author>
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<firstname>Al</firstname>
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<surname>Hoang</surname>
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<contrib>Contributed by </contrib>
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</author>
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</authorgroup>
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</sect2info>
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<!-- Feb 2004 -->
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<title>Setting Up Static Routes</title>
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<sect3>
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<title>Manual Configuration</title>
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<para>Let us assume we have a network as follows:</para>
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<literallayout class="monospaced">
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INTERNET
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| (10.0.0.1/24) Default Router to Internet
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|Interface xl0
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|10.0.0.10/24
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+------+
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| | RouterA
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| | (FreeBSD gateway)
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+------+
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| Interface xl1
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| 192.168.1.1/24
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+--------------------------------+
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Internal Net 1 | 192.168.1.2/24
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+------+
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| | RouterB
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| |
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+------+
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| 192.168.2.1/24
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Internal Net 2
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</literallayout>
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<para>In this scenario, <hostid>RouterA</hostid> is our &os;
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machine that is acting as a router to the rest of the
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Internet. It has a default route set to <hostid
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role="ipaddr">10.0.0.1</hostid> which allows it to connect
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with the outside world. We will assume that
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<hostid>RouterB</hostid> is already configured properly and
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knows how to get wherever it needs to go. (This is simple
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in this picture. Just add a default route on
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<hostid>RouterB</hostid> using <hostid
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role="ipaddr">192.168.1.1</hostid> as the gateway.)</para>
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<para>If we look at the routing table for
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<hostid>RouterA</hostid> we would see something like the
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following:</para>
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<screen>&prompt.user; <userinput>netstat -nr</userinput>
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Routing tables
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Internet:
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Destination Gateway Flags Refs Use Netif Expire
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default 10.0.0.1 UGS 0 49378 xl0
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127.0.0.1 127.0.0.1 UH 0 6 lo0
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10.0.0/24 link#1 UC 0 0 xl0
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192.168.1/24 link#2 UC 0 0 xl1</screen>
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<para>With the current routing table. <hostid>RouterA</hostid>
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will not be able to reach our Internal Net 2. It does not
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have a route for <hostid
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role="ipaddr">192.168.2.0/24</hostid>. One way to alleviate
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this is to manually add the route. The following command
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would add the Internal Net 2 network to
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<hostid>RouterA</hostid>'s routing table using <hostid
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role="ipaddr">192.168.1.2</hostid> as the next hop.</para>
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<screen>&prompt.root; <userinput>route add network 192.168.2.0/24 192.168.1.2</userinput></screen>
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<para>Now <hostid>RouterA</hostid> can reach any hosts on the
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<hostid role="ipaddr">192.168.2.0/24</hostid>
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network.</para>
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</sect3>
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<sect3>
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<title>Persistent Configuration</title>
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<para>The above example is perfect for configuring a static
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route on a running system. However, one problem is that the
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routing information will not persist if you reboot your &os;
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machine. The way to handle the addition of a static route
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is to put it in your <filename>/etc/rc.conf</filename>
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file:</para>
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<programlisting># Add Internal Net 2 as a static route
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static_routes="internalnet2"
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route_internalnet2="network 192.168.2.0/24 192.168.1.2"</programlisting>
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<para>The <literal>static_routes</literal> configuration
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variable is a list of strings seperated by a space. Each
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string references to a route name. In our above example we
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only have one string in <literal>static_routes</literal>.
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This string is <replaceable>internalnet2</replaceable>. We
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then add a configuration variable called
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<literal>route_<replaceable>internalnet2</replaceable></literal>
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where we put all of the configuration parameters we would
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give to the &man.route.8; command. For our example above we
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would have used the command:</para>
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<screen>&prompt.root; <userinput>route add network 192.168.2.0/24 192.168.1.2</userinput></screen>
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<para>so we need <literal>"network 192.168.2.0/24 192.168.1.2"</literal>.</para>
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<para>As said above, we can have more than one string in
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<literal>static_routes</literal>. This allows us to
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create multiple static routes. The following lines shows
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an example of adding static routes for the <hostid
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role="ipaddr">192.168.0.0/24</hostid> and <hostid
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role="ipaddr">192.168.1.0/24</hostid> networks on an imaginary
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router:</para>
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<programlisting>static_routes="net1 net2"
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route_net1="network 192.168.0.0/24 192.168.0.1"
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route_net2="network 192.168.1.0/24 192.168.1.1"</programlisting>
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</sect3>
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</sect2>
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<sect2>
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<title>Routing Propagation</title>
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<indexterm><primary>routing propagation</primary></indexterm>
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