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diff --git a/chapter07/network.xml b/chapter07/network.xml index c09f92431..ac6082271 100644 --- a/chapter07/network.xml +++ b/chapter07/network.xml @@ -24,6 +24,48 @@ class="directory">/etc/rc.d/rc*.d</filename>).</para> <sect2> + <title>Creating stable names for network interfaces</title> + + <para>Instructions in this section are optional if you have only one + network card.</para> + + <para>With Udev and modular network drivers, the network interface numbering + is not persistent across reboots by default, because the drivers are loaded + in parallel and, thus, in random order. For example, on a computer having + two network cards made by Intel and Realtek, the network card manufactured + by Intel may become <filename class="devicefile">eth0</filename> and the + Realtek card becomes <filename class="devicefile">eth1</filename>. In some + cases, after a reboot the cards get renumbered the other way around. To + avoid this, create Udev rules that assign stable names to network cards + based on their MAC addresses.</para> + + <para>First, find out the MAC addresses of your network cards:</para> + +<screen role="nodump"><userinput>grep -H . /sys/class/net/*/address</userinput></screen> + + <para>For each network card (but not for the loopback interface), + invent a descriptive name, such as <quote>realtek</quote>, and create + Udev rules similar to the following:</para> + +<screen role="nodump"><userinput>cat > /etc/udev/rules.d/26-network.rules << "EOF" +<literal>ACTION=="add", SUBSYSTEM=="net", SYSFS{address}=="<replaceable>52:54:00:12:34:56</replaceable>", NAME="<replaceable>realtek</replaceable>" +ACTION=="add", SUBSYSTEM=="net", SYSFS{address}=="<replaceable>00:a0:c9:78:9a:bc</replaceable>", NAME="<replaceable>intel</replaceable>"</literal> +EOF</userinput></screen> + + <para>These rules will always rename the network cards to + <quote>realtek</quote> and <quote>intel</quote>, independently of the + original numbering provided by the kernel. Use these names instead of + <quote>eth0</quote> in the network interface configuration files created + below.</para> + + <note> + <para>Persistent names must be different from the default network + interface names assigned by the kernel.</para> + </note> + + </sect2> + + <sect2> <title>Creating Network Interface Configuration Files</title> <para>Which interfaces are brought up and down by the network script |