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https://github.com/systemd/systemd.git
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2e229e0c4c
Two of the bits in the MAC address are set unconditioanlly, and the rest is randomized, make this clear in the documentation (as it currently read as if it was all random).
429 lines
16 KiB
XML
429 lines
16 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
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<!ENTITY % entities SYSTEM "custom-entities.ent" >
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%entities;
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]>
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<!--
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This file is part of systemd.
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Copyright 2014 Tom Gundersen
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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-->
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<refentry id="systemd.link">
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<refentryinfo>
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<title>systemd.link</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>Tom</firstname>
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<surname>Gundersen</surname>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>systemd.link</refentrytitle>
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<manvolnum>5</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>systemd.link</refname>
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<refpurpose>Network device configuration</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<para><filename><replaceable>link</replaceable>.link</filename></para>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para>Network link configuration is performed by the
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<command>net_setup_link</command> udev builtin.</para>
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<para>The link files are read from the files located in the system
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network directory <filename>&rootlibexecdir;/network</filename>,
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the volatile runtime network directory
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<filename>/run/systemd/network</filename>, and the local
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administration network directory
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<filename>&pkgsysconfdir;/network</filename>. Link files must have
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the extension <filename>.link</filename>; other extensions are
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ignored. All link files are collectively sorted and processed in
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lexical order, regardless of the directories in which they live.
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However, files with identical filenames replace each other. Files
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in <filename>/etc</filename> have the highest priority, files in
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<filename>/run</filename> take precedence over files with the same
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name in <filename>&rootprefix;/lib</filename>. This can be used to
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override a system-supplied link file with a local file if needed;
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a symlink in <filename>/etc</filename> with the same name as a
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link file in <filename>&rootprefix;/lib</filename>, pointing to
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<filename>/dev/null</filename>, disables the link file
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entirely.</para>
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<para>The link file contains a <literal>[Match]</literal> section,
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which determines if a given link file may be applied to a given
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device, as well as a <literal>[Link]</literal> section specifying
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how the device should be configured. The first (in lexical order)
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of the link files that matches a given device is applied. Note
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that a default file <filename>99-default.link</filename> is
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shipped by the system, any user-supplied
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<filename>.link</filename> should hence have a lexically earlier
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name to be considered at all.</para>
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</refsect1>
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<refsect1>
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<title>[Match] Section Options</title>
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<para>A link file is said to match a device if each of the entries
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in the <literal>[Match]</literal> section matches, or if the
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section is empty. The following keys are accepted:</para>
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<variablelist class='network-directives'>
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<varlistentry>
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<term><varname>MACAddress=</varname></term>
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<listitem>
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<para>The hardware address.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>OriginalName=</varname></term>
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<listitem>
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<para>A whitespace-separated list of shell-style globs matching
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the device name, as exposed by the udev property
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"INTERFACE". This can not be used to match on names that have
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already been changed from userspace. Caution is advised when matching on
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kernel-assigned names, as they are known to be unstable
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between reboots.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>Path=</varname></term>
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<listitem>
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<para>A whitespace-separated list of shell-style globs matching
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the persistent path, as exposed by the udev property
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<literal>ID_PATH</literal>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>Driver=</varname></term>
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<listitem>
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<para>A whitespace-separated list of shell-style globs matching
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the driver currently bound to the device,
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as exposed by the udev property <literal>DRIVER</literal>
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of its parent device, or if that is not set, the
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driver as exposed by <literal>ethtool -i</literal>
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of the device itself.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>Type=</varname></term>
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<listitem>
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<para>A whitespace-separated list of shell-style globs matching
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the device type, as exposed by the udev
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property <literal>DEVTYPE</literal>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>Host=</varname></term>
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<listitem>
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<para>Matches against the hostname or machine
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ID of the host. See <literal>ConditionHost=</literal> in
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<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
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for details.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>Virtualization=</varname></term>
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<listitem>
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<para>Checks whether the system is executed in
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a virtualized environment and optionally test
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whether it is a specific implementation. See
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<literal>ConditionVirtualization=</literal> in
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<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
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for details.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>KernelCommandLine=</varname></term>
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<listitem>
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<para>Checks whether a specific kernel command line option
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is set (or if prefixed with the exclamation mark unset). See
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<literal>ConditionKernelCommandLine=</literal> in
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<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
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for details.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>Architecture=</varname></term>
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<listitem>
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<para>Checks whether the system is running on a specific
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architecture. See <literal>ConditionArchitecture=</literal>
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in
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<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
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for details.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>[Link] Section Options</title>
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<para>The <literal>[Link]</literal> section accepts the following
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keys:</para>
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<variablelist class='network-directives'>
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<varlistentry>
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<term><varname>Description=</varname></term>
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<listitem>
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<para>A description of the device.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>Alias=</varname></term>
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<listitem>
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<para>The <literal>ifalias</literal> is set to this
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value.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>MACAddressPolicy=</varname></term>
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<listitem>
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<para>The policy by which the MAC address should be set. The
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available policies are:
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</para>
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<variablelist>
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<varlistentry>
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<term><literal>persistent</literal></term>
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<listitem>
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<para>If the hardware has a persistent MAC address, as
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most hardware should, and if it is used by the kernel,
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nothing is done. Otherwise, a new MAC address is
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generated which is guaranteed to be the same on every
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boot for the given machine and the given device, but
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which is otherwise random. This feature depends on ID_NET_NAME_*
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properties existing for the link, on hardware where these
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properties are not set the generation of a persistent MAC address
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will fail.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>random</literal></term>
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<listitem>
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<para>If the kernel is using a random MAC address,
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nothing is done. Otherwise, a new address is randomly
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generated each time the device appears, typically at
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boot. Either way the random address will have the
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<literal>unicast</literal> and
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<literal>locally administered</literal> bits set.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>MACAddress=</varname></term>
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<listitem>
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<para>The MAC address to use, if no
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<literal>MACAddressPolicy=</literal>
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is specified.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>NamePolicy=</varname></term>
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<listitem>
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<para>An ordered, space-separated list of policies by which
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the interface name should be set.
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<literal>NamePolicy</literal> may be disabled by specifying
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<literal>net.ifnames=0</literal> on the kernel command line.
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Each of the policies may fail, and the first successful one
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is used. The name is not set directly, but is exported to
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udev as the property <literal>ID_NET_NAME</literal>, which
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is, by default, used by a udev rule to set
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<literal>NAME</literal>. If the name has already been set by
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userspace, no renaming is performed. The available policies
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are:</para>
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<variablelist>
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<varlistentry>
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<term><literal>kernel</literal></term>
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<listitem>
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<para>If the kernel claims that the name it has set
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for a device is predictable, then no renaming is
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performed.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>database</literal></term>
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<listitem>
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<para>The name is set based on entries in the udev's
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Hardware Database with the key
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<literal>ID_NET_NAME_FROM_DATABASE</literal>.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>onboard</literal></term>
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<listitem>
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<para>The name is set based on information given by
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the firmware for on-board devices, as exported by the
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udev property <literal>ID_NET_NAME_ONBOARD</literal>.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>slot</literal></term>
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<listitem>
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<para>The name is set based on information given by
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the firmware for hot-plug devices, as exported by the
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udev property <literal>ID_NET_NAME_SLOT</literal>.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>path</literal></term>
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<listitem>
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<para>The name is set based on the device's physical
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location, as exported by the udev property
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<literal>ID_NET_NAME_PATH</literal>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>mac</literal></term>
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<listitem>
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<para>The name is set based on the device's persistent
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MAC address, as exported by the udev property
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<literal>ID_NET_NAME_MAC</literal>.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>Name=</varname></term>
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<listitem>
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<para>The interface name to use in case all the
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policies specified in
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<varname>NamePolicy=</varname> fail, or in case
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<varname>NamePolicy=</varname> is missing or
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disabled.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>MTUBytes=</varname></term>
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<listitem>
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<para>The maximum transmission unit in bytes to set for the
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device. The usual suffixes K, M, G, are supported and are
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understood to the base of 1024.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>BitsPerSecond=</varname></term>
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<listitem>
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<para>The speed to set for the device, the value is rounded
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down to the nearest Mbps. The usual suffixes K, M, G, are
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supported and are understood to the base of 1000.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>Duplex=</varname></term>
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<listitem>
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<para>The duplex mode to set for the device. The accepted
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values are <literal>half</literal> and
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<literal>full</literal>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>WakeOnLan=</varname></term>
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<listitem>
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<para>The Wake-on-LAN policy to set for the device. The
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supported values are:</para>
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<variablelist>
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<varlistentry>
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<term><literal>phy</literal></term>
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<listitem>
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<para>Wake on PHY activity.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>magic</literal></term>
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<listitem>
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<para>Wake on receipt of a magic packet.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>off</literal></term>
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<listitem>
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<para>Never wake.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Example</title>
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<example>
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<title>&pkgsysconfdir;/network/wireless.link</title>
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<programlisting>[Match]
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MACAddress=12:34:56:78:9a:bc
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Driver=brcmsmac
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Path=pci-0000:02:00.0-*
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Type=wlan
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Virtualization=no
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Host=my-laptop
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Architecture=x86-64
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[Link]
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Name=wireless0
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MTUBytes=1450
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BitsPerSecond=10M
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WakeOnLan=magic
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MACAddress=cb:a9:87:65:43:21</programlisting>
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</example>
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</refsect1>
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<refsect1>
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<title>See Also</title>
|
|
<para>
|
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<citerefentry>
|
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<refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum>
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</citerefentry>,
|
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<citerefentry>
|
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<refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum>
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</citerefentry>,
|
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<citerefentry>
|
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<refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum>
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</citerefentry>,
|
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<citerefentry>
|
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<refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum>
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</citerefentry>
|
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</para>
|
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</refsect1>
|
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|
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</refentry>
|