X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=man%2Fsysctl.d.xml;h=c67a199fb518513e39677a66ac59c1f805346fea;hp=51afbfa77a158e86eddc5be629f48f82ee8702a6;hb=de59d29e8abc32ff8e5de6a36ddf9d04d63ccb47;hpb=db1413d7380acacc4e50faf801ca0d401da89764

diff --git a/man/sysctl.d.xml b/man/sysctl.d.xml
index 51afbfa77..c67a199fb 100644
--- a/man/sysctl.d.xml
+++ b/man/sysctl.d.xml
@@ -1,5 +1,4 @@
-<?xml version="1.0"?>
-<!--*-nxml-*-->
+<?xml version="1.0"?> <!--*-nxml-*-->
 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
 <!--
   This file is part of systemd.
@@ -7,19 +6,20 @@
   Copyright 2011 Lennart Poettering
 
   systemd is free software; you can redistribute it and/or modify it
-  under the terms of the GNU General Public License as published by
-  the Free Software Foundation; either version 2 of the License, or
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
   (at your option) any later version.
 
   systemd is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-  General Public License for more details.
+  Lesser General Public License for more details.
 
-  You should have received a copy of the GNU General Public License
+  You should have received a copy of the GNU Lesser General Public License
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 -->
-<refentry id="sysctl.d">
+<refentry id="sysctl.d"
+          xmlns:xi="http://www.w3.org/2001/XInclude">
 
         <refentryinfo>
                 <title>sysctl.d</title>
@@ -46,55 +46,118 @@
         </refnamediv>
 
         <refsynopsisdiv>
-                <para><filename>/usr/lib/sysctl.d/*.conf</filename></para>
                 <para><filename>/etc/sysctl.d/*.conf</filename></para>
                 <para><filename>/run/sysctl.d/*.conf</filename></para>
+                <para><filename>/usr/lib/sysctl.d/*.conf</filename></para>
         </refsynopsisdiv>
 
         <refsect1>
                 <title>Description</title>
 
-		<para><command>systemd</command> uses
-		<filename>/etc/sysctl.d/</filename> to configure
-		<citerefentry><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
-		kernel parameters to load during boot. Each
-		configuration file is named in the style of
-		<filename>/etc/sysctl.d/&lt;program&gt;.conf</filename>.</para>
+                <para>At boot,
+                <citerefentry><refentrytitle>systemd-sysctl.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+                reads configuration files from the above directories
+                to configure
+                <citerefentry><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+                kernel parameters.</para>
         </refsect1>
 
         <refsect1>
-		<title>Configuration Format</title>
-
-		<para>The configuration files should simply contain a
-		list of variable assignments, separated by
-		newlines. Empty lines and lines whose first
-		non-whitespace character is # or ; are ignored.</para>
-
-                <para>Note that both / and . are accepted as
-                separators in sysctl variable names.</para>
-
-                <para>Files in <filename>/etc/</filename> overwrite
-                files with the same name in <filename>/usr/lib/</filename>.
-                Files in <filename>/run</filename> overwrite files with
-                the same name in <filename>/etc/</filename> and
-                <filename>/usr/lib/</filename>. Packages should install their
-                configuration files in <filename>/usr/lib/</filename>, files
-                in <filename>/etc/</filename> are reserved for the local
-                administration, which possibly decides to overwrite the
-                configurations installed from packages. All files are sorted
-                by filename in alphabetical order, regardless in which of the
-                directories they reside, to ensure that a specific
-                configuration file takes precedence over another file with
-                an alphabetically later name.</para>
+                <title>Configuration Format</title>
+
+                <para>The configuration files contain a list of
+                variable assignments, separated by newlines. Empty
+                lines and lines whose first non-whitespace character
+                is <literal>#</literal> or <literal>;</literal> are
+                ignored.</para>
+
+                <para>Note that either <literal>/</literal> or
+                <literal>.</literal> may be used as separators within
+                sysctl variable names. If the first separator is a
+                slash, remaining slashes and dots are left intact. If
+                the first separator is a dot, dots and slashes are
+                interchanged. <literal>kernel.domainname=foo</literal>
+                and <literal>kernel/domainname=foo</literal> are
+                equivalent and will cause <literal>foo</literal> to
+                be written to
+                <filename>/proc/sys/kernel/domainname</filename>.
+                Either
+                <literal>net.ipv4.conf.enp3s0/200.forwarding</literal>
+                or
+                <literal>net/ipv4/conf/enp3s0.200/forwarding</literal>
+                may be used to refer to
+                <filename>/proc/sys/net/ipv4/conf/enp3s0.200/forwarding</filename>.
+                </para>
+
+                <para>The settings configured with
+                <filename>sysctl.d</filename> files will be applied
+                early on boot. The network interface-specific options
+                will also be applied individually for each network
+                interface as it shows up in the system. (More
+                specifically,
+                <filename>net.ipv4.conf.*</filename>,
+                <filename>net.ipv6.conf.*</filename>,
+                <filename>net.ipv4.neigh.*</filename> and <filename>net.ipv6.neigh.*</filename>).</para>
+
+                <para>Many sysctl parameters only become available
+                when certain kernel modules are loaded. Modules are
+                usually loaded on demand, e.g. when certain hardware
+                is plugged in or network brought up. This means that
+                <citerefentry><refentrytitle>systemd-sysctl.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> which runs
+                during early boot will not configure such parameters
+                if they become available after it has run. To
+                set such parameters, it is recommended to add
+                an <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry> rule to set those parameters when they become
+                available. Alternatively, a slightly simpler and
+                less efficient option is to add the module to
+                <citerefentry><refentrytitle>modules-load.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>, causing it to be loaded statically
+                before sysctl settings are applied (see
+                example below).</para>
         </refsect1>
 
+        <xi:include href="standard-conf.xml" xpointer="confd" />
+
         <refsect1>
-                <title>Example</title>
+                <title>Examples</title>
+                <example>
+                        <title>Set kernel YP domain name</title>
+                        <para><filename>/etc/sysctl.d/domain-name.conf</filename>:
+                        </para>
+
+                        <programlisting>kernel.domainname=example.com</programlisting>
+                </example>
+
                 <example>
-                        <title>/etc/sysctl.d/domain-name.conf example:</title>
+                        <title>Disable packet filter on bridged packets (method one)</title>
+                        <para><filename>/etc/udev/rules.d/99-bridge.rules</filename>:
+                        </para>
+
+                        <programlisting>ACTION=="add", SUBSYSTEM=="module", KERNEL=="bridge", RUN+="/usr/lib/systemd/systemd-sysctl --prefix=/net/bridge"
+</programlisting>
+
+                        <para><filename>/etc/sysctl.d/bridge.conf</filename>:
+                        </para>
+
+                        <programlisting>net.bridge.bridge-nf-call-ip6tables = 0
+net.bridge.bridge-nf-call-iptables = 0
+net.bridge.bridge-nf-call-arptables = 0
+</programlisting>
+                </example>
+
+                <example>
+                        <title>Disable packet filter on bridged packets (method two)</title>
+                        <para><filename>/etc/modules-load.d/bridge.conf</filename>:
+                        </para>
+
+                        <programlisting>bridge</programlisting>
+
+                        <para><filename>/etc/sysctl.d/bridge.conf</filename>:
+                        </para>
 
-                        <programlisting># Set kernel YP domain name
-kernel.domainname=example.com</programlisting>
+                        <programlisting>net.bridge.bridge-nf-call-ip6tables = 0
+net.bridge.bridge-nf-call-iptables = 0
+net.bridge.bridge-nf-call-arptables = 0
+</programlisting>
                 </example>
         </refsect1>
 
@@ -102,8 +165,11 @@ kernel.domainname=example.com</programlisting>
                 <title>See Also</title>
                 <para>
                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+                        <citerefentry><refentrytitle>systemd-sysctl.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+                        <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
                         <citerefentry><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
-                        <citerefentry><refentrytitle>sysctl.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+                        <citerefentry><refentrytitle>sysctl.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+                        <citerefentry><refentrytitle>modprobe</refentrytitle><manvolnum>8</manvolnum></citerefentry>
                 </para>
         </refsect1>