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+<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
+<!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.
+
+ Copyright 2013 Tom Gundersen
+
+ systemd is free software; you can redistribute it and/or modify it
+ 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
+ Lesser General Public License for more details.
+
+ 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="systemd.network" conditional='ENABLE_NETWORKD'>
+
+ <refentryinfo>
+ <title>systemd.network</title>
+ <productname>systemd</productname>
+
+ <authorgroup>
+ <author>
+ <contrib>Developer</contrib>
+ <firstname>Tom</firstname>
+ <surname>Gundersen</surname>
+ <email>teg@jklm.no</email>
+ </author>
+ </authorgroup>
+ </refentryinfo>
+
+ <refmeta>
+ <refentrytitle>systemd.network</refentrytitle>
+ <manvolnum>5</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+ <refname>systemd.network</refname>
+ <refpurpose>Network configuration</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <para><filename><replaceable>network</replaceable>.network</filename></para>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para>Network setup is performed by
+ <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
+ </para>
+
+ <para>The main network file must have the extension <filename>.network</filename>; other
+ extensions are ignored. Networks are applied to links whenever the links appear.</para>
+
+ <para>The <filename>.network</filename> files are read from the files located in the system
+ network directory <filename>/usr/lib/systemd/network</filename>, the volatile runtime network
+ directory <filename>/run/systemd/network</filename> and the local administration network
+ directory <filename>/etc/systemd/network</filename>. All configuration files are collectively
+ sorted and processed in lexical order, regardless of the directories in which they live.
+ However, files with identical filenames replace each other. Files in <filename>/etc</filename>
+ have the highest priority, files in <filename>/run</filename> take precedence over files with
+ the same name in <filename>/usr/lib</filename>. This can be used to override a system-supplied
+ configuration file with a local file if needed. As a special case, an empty file (file size 0)
+ or symlink with the same name pointing to <filename>/dev/null</filename> disables the
+ configuration file entirely (it is "masked").</para>
+
+ <para>Along with the network file <filename>foo.network</filename>, a "drop-in" directory
+ <filename>foo.network.d/</filename> may exist. All files with the suffix
+ <literal>.conf</literal> from this directory will be parsed after the file itself is
+ parsed. This is useful to alter or add configuration settings, without having to modify the main
+ configuration file. Each drop-in file must have appropriate section headers.</para>
+
+ <para>In addition to <filename>/etc/systemd/network</filename>, drop-in <literal>.d</literal>
+ directories can be placed in <filename>/usr/lib/systemd/network</filename> or
+ <filename>/run/systemd/network</filename> directories. Drop-in files in
+ <filename>/etc</filename> take precedence over those in <filename>/run</filename> which in turn
+ take precedence over those in <filename>/usr/lib</filename>. Drop-in files under any of these
+ directories take precedence over the main netdev file wherever located. (Of course, since
+ <filename>/run</filename> is temporary and <filename>/usr/lib</filename> is for vendors, it is
+ unlikely drop-ins should be used in either of those places.)</para>
+
+ <para>Note that an interface without any static IPv6 addresses configured, and neither DHCPv6
+ nor IPv6LL enabled, shall be considered to have no IPv6 support. IPv6 will be automatically
+ disabled for that interface by writing "1" to
+ <filename>/proc/sys/net/ipv6/conf/<replaceable>ifname</replaceable>/disable_ipv6</filename>.
+ </para>
+ </refsect1>
+
+ <refsect1>
+ <title>[Match] Section Options</title>
+
+ <para>The network file contains a <literal>[Match]</literal>
+ section, which determines if a given network file may be applied
+ to a given device; and a <literal>[Network]</literal> section
+ specifying how the device should be configured. The first (in
+ lexical order) of the network files that matches a given device
+ is applied, all later files are ignored, even if they match as
+ well.</para>
+
+ <para>A network file is said to match a device if each of the
+ entries in the <literal>[Match]</literal> section matches, or if
+ the section is empty. The following keys are accepted:</para>
+
+ <variablelist class='network-directives'>
+ <varlistentry>
+ <term><varname>MACAddress=</varname></term>
+ <listitem>
+ <para>The hardware address of the interface (use full colon-delimited hexadecimal, e.g.,
+ 01:23:45:67:89:ab).</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Path=</varname></term>
+ <listitem>
+ <para>A whitespace-separated list of shell-style globs
+ matching the persistent path, as exposed by the udev
+ property <literal>ID_PATH</literal>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Driver=</varname></term>
+ <listitem>
+ <para>A whitespace-separated list of shell-style globs
+ matching the driver currently bound to the device, as
+ exposed by the udev property <literal>DRIVER</literal>
+ of its parent device, or if that is not set the driver
+ as exposed by <literal>ethtool -i</literal> of the
+ device itself.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Type=</varname></term>
+ <listitem>
+ <para>A whitespace-separated list of shell-style globs
+ matching the device type, as exposed by the udev property
+ <literal>DEVTYPE</literal>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Name=</varname></term>
+ <listitem>
+ <para>A whitespace-separated list of shell-style globs
+ matching the device name, as exposed by the udev property
+ <literal>INTERFACE</literal>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Host=</varname></term>
+ <listitem>
+ <para>Matches against the hostname or machine ID of the
+ host. See <literal>ConditionHost=</literal> in
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Virtualization=</varname></term>
+ <listitem>
+ <para>Checks whether the system is executed in a virtualized
+ environment and optionally test whether it is a specific
+ implementation. See <literal>ConditionVirtualization=</literal> in
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>KernelCommandLine=</varname></term>
+ <listitem>
+ <para>Checks whether a specific kernel command line option is
+ set (or if prefixed with the exclamation mark unset). See
+ <literal>ConditionKernelCommandLine=</literal> in
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Architecture=</varname></term>
+ <listitem>
+ <para>Checks whether the system is running on a specific
+ architecture. See <literal>ConditionArchitecture=</literal> in
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+
+ </refsect1>
+
+ <refsect1>
+ <title>[Link] Section Options</title>
+
+ <para> The <literal>[Link]</literal> section accepts the following keys:</para>
+
+ <variablelist class='network-directives'>
+ <varlistentry>
+ <term><varname>MACAddress=</varname></term>
+ <listitem>
+ <para>The hardware address to set for the device.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>MTUBytes=</varname></term>
+ <listitem>
+ <para>The maximum transmission unit in bytes to set for the
+ device. The usual suffixes K, M, G, are supported and are
+ understood to the base of 1024.</para>
+ <para>Note that if IPv6 is enabled on the interface, and the MTU is chosen
+ below 1280 (the minimum MTU for IPv6) it will automatically be increased to this value.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>ARP=</varname></term>
+ <listitem>
+ <para> A boolean. Enables or disables the ARP (low-level Address Resolution Protocol)
+ for this interface. Defaults to unset, which means that the kernel default will be used.</para>
+ <para> For example, disabling ARP is useful when creating multiple MACVLAN or VLAN virtual
+ interfaces atop a single lower-level physical interface, which will then only serve as a
+ link/"bridge" device aggregating traffic to the same physical link and not participate in
+ the network otherwise.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>[Network] Section Options</title>
+
+ <para>The <literal>[Network]</literal> section accepts the following keys:</para>
+
+ <variablelist class='network-directives'>
+ <varlistentry>
+ <term><varname>Description=</varname></term>
+ <listitem>
+ <para>A description of the device. This is only used for
+ presentation purposes.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>DHCP=</varname></term>
+ <listitem>
+ <para>Enables DHCPv4 and/or DHCPv6 client support. Accepts
+ <literal>yes</literal>, <literal>no</literal>,
+ <literal>ipv4</literal>, or <literal>ipv6</literal>.</para>
+
+ <para>Note that DHCPv6 will by default be triggered by Router
+ Advertisement, if that is enabled, regardless of this parameter.
+ By enabling DHCPv6 support explicitly, the DHCPv6 client will
+ be started regardless of the presence of routers on the link,
+ or what flags the routers pass. See
+ <literal>IPv6AcceptRA=</literal>.</para>
+
+ <para>Furthermore, note that by default the domain name
+ specified through DHCP is not used for name resolution.
+ See option <option>UseDomains=</option> below.</para>
+
+ <para>See the <literal>[DHCP]</literal> section below for further configuration options for the DHCP client
+ support.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>DHCPServer=</varname></term>
+ <listitem>
+ <para>A boolean. Enables DHCPv4 server support. Defaults
+ to <literal>no</literal>. Further settings for the DHCP
+ server may be set in the <literal>[DHCPServer]</literal>
+ section described below.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>LinkLocalAddressing=</varname></term>
+ <listitem>
+ <para>Enables link-local address autoconfiguration. Accepts
+ <literal>yes</literal>, <literal>no</literal>,
+ <literal>ipv4</literal>, or <literal>ipv6</literal>. Defaults to
+ <literal>ipv6</literal>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>IPv4LLRoute=</varname></term>
+ <listitem>
+ <para>A boolean. When true, sets up the route needed for
+ non-IPv4LL hosts to communicate with IPv4LL-only hosts. Defaults
+ to false.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>IPv6Token=</varname></term>
+ <listitem>
+ <para>An IPv6 address with the top 64 bits unset. When set, indicates the
+ 64-bit interface part of SLAAC IPv6 addresses for this link. Note that
+ the token is only ever used for SLAAC, and not for DHCPv6 addresses, even
+ in the case DHCP is requested by router advertisement. By default, the
+ token is autogenerated.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>LLMNR=</varname></term>
+ <listitem>
+ <para>A boolean or <literal>resolve</literal>. When true,
+ enables <ulink
+ url="https://tools.ietf.org/html/rfc4795">Link-Local
+ Multicast Name Resolution</ulink> on the link. When set to
+ <literal>resolve</literal>, only resolution is enabled,
+ but not host registration and announcement. Defaults to
+ true. This setting is read by
+ <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>MulticastDNS=</varname></term>
+ <listitem>
+ <para>A boolean or <literal>resolve</literal>. When true,
+ enables <ulink
+ url="https://tools.ietf.org/html/rfc6762">Multicast
+ DNS</ulink> support on the link. When set to
+ <literal>resolve</literal>, only resolution is enabled,
+ but not host or service registration and
+ announcement. Defaults to false. This setting is read by
+ <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>DNSSEC=</varname></term>
+ <listitem>
+ <para>A boolean or
+ <literal>allow-downgrade</literal>. When true, enables
+ <ulink
+ url="https://tools.ietf.org/html/rfc4033">DNSSEC</ulink>
+ DNS validation support on the link. When set to
+ <literal>allow-downgrade</literal>, compatibility with
+ non-DNSSEC capable networks is increased, by automatically
+ turning off DNSEC in this case. This option defines a
+ per-interface setting for
+ <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s
+ global <varname>DNSSEC=</varname> option. Defaults to
+ false. This setting is read by
+ <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>DNSSECNegativeTrustAnchors=</varname></term>
+ <listitem><para>A space-separated list of DNSSEC negative
+ trust anchor domains. If specified and DNSSEC is enabled,
+ look-ups done via the interface's DNS server will be subject
+ to the list of negative trust anchors, and not require
+ authentication for the specified domains, or anything below
+ it. Use this to disable DNSSEC authentication for specific
+ private domains, that cannot be proven valid using the
+ Internet DNS hierarchy. Defaults to the empty list. This
+ setting is read by
+ <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>LLDP=</varname></term>
+ <listitem>
+ <para>Controls support for Ethernet LLDP packet reception. LLDP is a link-layer protocol commonly
+ implemented on professional routers and bridges which announces which physical port a system is connected
+ to, as well as other related data. Accepts a boolean or the special value
+ <literal>routers-only</literal>. When true, incoming LLDP packets are accepted and a database of all LLDP
+ neighbors maintained. If <literal>routers-only</literal> is set only LLDP data of various types of routers
+ is collected and LLDP data about other types of devices ignored (such as stations, telephones and
+ others). If false, LLDP reception is disabled. Defaults to <literal>routers-only</literal>. Use
+ <citerefentry><refentrytitle>networkctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> to query the
+ collected neighbor data. LLDP is only available on Ethernet links. See <varname>EmitLLDP=</varname> below
+ for enabling LLDP packet emission from the local system.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>EmitLLDP=</varname></term>
+ <listitem>
+ <para>Controls support for Ethernet LLDP packet emission. Accepts a boolean parameter or the special values
+ <literal>nearest-bridge</literal>, <literal>non-tpmr-bridge</literal> and
+ <literal>customer-bridge</literal>. Defaults to false, which turns off LLDP packet emission. If not false,
+ a short LLDP packet with information about the local system is sent out in regular intervals on the
+ link. The LLDP packet will contain information about the local host name, the local machine ID (as stored
+ in <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>) and the
+ local interface name, as well as the pretty hostname of the system (as set in
+ <citerefentry><refentrytitle>machine-info</refentrytitle><manvolnum>5</manvolnum></citerefentry>). LLDP
+ emission is only available on Ethernet links. Note that this setting passes data suitable for
+ identification of host to the network and should thus not be enabled on untrusted networks, where such
+ identification data should not be made available. Use this option to permit other systems to identify on
+ which interfaces they are connected to this system. The three special values control propagation of the
+ LLDP packets. The <literal>nearest-bridge</literal> setting permits propagation only to the nearest
+ connected bridge, <literal>non-tpmr-bridge</literal> permits propagation across Two-Port MAC Relays, but
+ not any other bridges, and <literal>customer-bridge</literal> permits propagation until a customer bridge
+ is reached. For details about these concepts, see <ulink
+ url="http://standards.ieee.org/getieee802/download/802.1AB-2009.pdf">IEEE 802.1AB-2009</ulink>. Note that
+ configuring this setting to true is equivalent to <literal>nearest-bridge</literal>, the recommended and
+ most restricted level of propagation. See <varname>LLDP=</varname> above for an option to enable LLDP
+ reception.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>BindCarrier=</varname></term>
+ <listitem>
+ <para>A link name or a list of link names. When set, controls the behavior of the current
+ link. When all links in the list are in an operational down state, the current link is brought
+ down. When at least one link has carrier, the current interface is brought up.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Address=</varname></term>
+ <listitem>
+ <para>A static IPv4 or IPv6 address and its prefix length,
+ separated by a <literal>/</literal> character. Specify
+ this key more than once to configure several addresses.
+ The format of the address must be as described in
+ <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+ This is a short-hand for an [Address] section only
+ containing an Address key (see below). This option may be
+ specified more than once.
+ </para>
+
+ <para>If the specified address is 0.0.0.0 (for IPv4) or
+ [::] (for IPv6), a new address range of the requested size
+ is automatically allocated from a system-wide pool of
+ unused ranges. The allocated range is checked against all
+ current network interfaces and all known network
+ configuration files to avoid address range conflicts. The
+ default system-wide pool consists of 192.168.0.0/16,
+ 172.16.0.0/12 and 10.0.0.0/8 for IPv4, and fc00::/7 for
+ IPv6. This functionality is useful to manage a large
+ number of dynamically created network interfaces with the
+ same network configuration and automatic address range
+ assignment.</para>
+
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Gateway=</varname></term>
+ <listitem>
+ <para>The gateway address, which must be in the format
+ described in
+ <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+ This is a short-hand for a [Route] section only containing
+ a Gateway key. This option may be specified more than
+ once.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>DNS=</varname></term>
+ <listitem>
+ <para>A DNS server address, which must be in the format
+ described in
+ <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+ This option may be specified more than once. This setting is read by
+ <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Domains=</varname></term>
+ <listitem>
+ <para>A list of domains which should be resolved using the DNS servers on this link. Each item in the list
+ should be a domain name, optionally prefixed with a tilde (<literal>~</literal>). The domains with the
+ prefix are called "routing-only domains". The domains without the prefix are called "search domains" and
+ are first used as search suffixes for extending single-label host names (host names containing no dots) to
+ become fully qualified domain names (FQDNs). If a single-label host name is resolved on this interface,
+ each of the specified search domains are appended to it in turn, converting it into a fully qualified
+ domain name, until one of them may be successfully resolved.</para>
+
+ <para>Both "search" and "routing-only" domains are used for routing of DNS queries: look-ups for host names
+ ending in those domains (hence also single label names, if any "search domains" are listed), are routed to
+ the DNS servers configured for this interface. The domain routing logic is particularly useful on
+ multi-homed hosts with DNS servers serving particular private DNS zones on each interface.</para>
+
+ <para>The "routing-only" domain <literal>~.</literal> (the tilde indicating definition of a routing domain,
+ the dot referring to the DNS root domain which is the implied suffix of all valid DNS names) has special
+ effect. It causes all DNS traffic which does not match another configured domain routing entry to be routed
+ to DNS servers specified for this interface. This setting is useful to prefer a certain set of DNS servers
+ if a link on which they are connected is available.</para>
+
+ <para>This setting is read by
+ <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
+ "Search domains" correspond to the <varname>domain</varname> and <varname>search</varname> entries in
+ <citerefentry><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+ Domain name routing has no equivalent in the traditional glibc API, which has no concept of domain
+ name servers limited to a specific link.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>NTP=</varname></term>
+ <listitem>
+ <para>An NTP server address. This option may be specified more than once. This setting is read by
+ <citerefentry><refentrytitle>systemd-timesyncd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>IPForward=</varname></term>
+ <listitem><para>Configures IP packet forwarding for the
+ system. If enabled, incoming packets on any network
+ interface will be forwarded to any other interfaces
+ according to the routing table. Takes either a boolean
+ argument, or the values <literal>ipv4</literal> or
+ <literal>ipv6</literal>, which only enable IP packet
+ forwarding for the specified address family. This controls
+ the <filename>net.ipv4.ip_forward</filename> and
+ <filename>net.ipv6.conf.all.forwarding</filename> sysctl
+ options of the network interface (see <ulink
+ url="https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt</ulink>
+ for details about sysctl options). Defaults to
+ <literal>no</literal>.</para>
+
+ <para>Note: this setting controls a global kernel option,
+ and does so one way only: if a network that has this setting
+ enabled is set up the global setting is turned on. However,
+ it is never turned off again, even after all networks with
+ this setting enabled are shut down again.</para>
+
+ <para>To allow IP packet forwarding only between specific
+ network interfaces use a firewall.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>IPMasquerade=</varname></term>
+ <listitem><para>Configures IP masquerading for the network
+ interface. If enabled, packets forwarded from the network
+ interface will be appear as coming from the local host.
+ Takes a boolean argument. Implies
+ <varname>IPForward=ipv4</varname>. Defaults to
+ <literal>no</literal>.</para></listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>IPv6PrivacyExtensions=</varname></term>
+ <listitem><para>Configures use of stateless temporary
+ addresses that change over time (see <ulink
+ url="https://tools.ietf.org/html/rfc4941">RFC 4941</ulink>,
+ Privacy Extensions for Stateless Address Autoconfiguration
+ in IPv6). Takes a boolean or the special values
+ <literal>prefer-public</literal> and
+ <literal>kernel</literal>. When true, enables the privacy
+ extensions and prefers temporary addresses over public
+ addresses. When <literal>prefer-public</literal>, enables the
+ privacy extensions, but prefers public addresses over
+ temporary addresses. When false, the privacy extensions
+ remain disabled. When <literal>kernel</literal>, the kernel's
+ default setting will be left in place. Defaults to
+ <literal>no</literal>.</para></listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>IPv6AcceptRA=</varname></term>
+ <listitem><para>Enable or disable IPv6 Router Advertisement (RA) reception support for the interface. Takes
+ a boolean parameter. If true, RAs are accepted; if false, RAs are ignored, independently of the local
+ forwarding state. When not set, the kernel default is used, and RAs are accepted only when local forwarding
+ is disabled for that interface. When RAs are accepted, they may trigger the start of the DHCPv6 client if
+ the relevant flags are set in the RA data, or if no routers are found on the link.</para>
+
+ <para>Further settings for the IPv6 RA support may be configured in the
+ <literal>[IPv6AcceptRA]</literal> section, see below.</para>
+
+ <para>Also see <ulink
+ url="https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt</ulink> in the kernel
+ documentation regarding <literal>accept_ra</literal>, but note that systemd's setting of
+ <constant>1</constant> (i.e. true) corresponds to kernel's setting of <constant>2</constant>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>IPv6DuplicateAddressDetection=</varname></term>
+ <listitem><para>Configures the amount of IPv6 Duplicate
+ Address Detection (DAD) probes to send. Defaults to unset.
+ </para></listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>IPv6HopLimit=</varname></term>
+ <listitem><para>Configures IPv6 Hop Limit. For each router that
+ forwards the packet, the hop limit is decremented by 1. When the
+ hop limit field reaches zero, the packet is discarded.
+ Defaults to unset.
+ </para></listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>ProxyARP=</varname></term>
+ <listitem><para>A boolean. Configures proxy ARP. Proxy ARP is the technique in which one host,
+ usually a router, answers ARP requests intended for another machine. By "faking" its identity,
+ the router accepts responsibility for routing packets to the "real" destination. (see <ulink
+ url="https://tools.ietf.org/html/rfc1027">RFC 1027</ulink>.
+ Defaults to unset.
+ </para></listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Bridge=</varname></term>
+ <listitem>
+ <para>The name of the bridge to add the link to.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Bond=</varname></term>
+ <listitem>
+ <para>The name of the bond to add the link to.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>VRF=</varname></term>
+ <listitem>
+ <para>The name of the VRF to add the link to.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>VLAN=</varname></term>
+ <listitem>
+ <para>The name of a VLAN to create on the link. This
+ option may be specified more than once.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>MACVLAN=</varname></term>
+ <listitem>
+ <para>The name of a MACVLAN to create on the link. This
+ option may be specified more than once.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>VXLAN=</varname></term>
+ <listitem>
+ <para>The name of a VXLAN to create on the link. This
+ option may be specified more than once.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Tunnel=</varname></term>
+ <listitem>
+ <para>The name of a Tunnel to create on the link. This
+ option may be specified more than once.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+
+ </refsect1>
+
+ <refsect1>
+ <title>[Address] Section Options</title>
+
+ <para>An <literal>[Address]</literal> section accepts the
+ following keys. Specify several <literal>[Address]</literal>
+ sections to configure several addresses.</para>
+
+ <variablelist class='network-directives'>
+ <varlistentry>
+ <term><varname>Address=</varname></term>
+ <listitem>
+ <para>As in the <literal>[Network]</literal> section. This
+ key is mandatory.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Peer=</varname></term>
+ <listitem>
+ <para>The peer address in a point-to-point connection.
+ Accepts the same format as the <literal>Address</literal>
+ key.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Broadcast=</varname></term>
+ <listitem>
+ <para>The broadcast address, which must be in the format
+ described in
+ <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+ This key only applies to IPv4 addresses. If it is not
+ given, it is derived from the <literal>Address</literal>
+ key.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Label=</varname></term>
+ <listitem>
+ <para>An address label.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>PreferredLifetime=</varname></term>
+ <listitem>
+ <para>Allows the default "preferred lifetime" of the address to be overridden.
+ Only three settings are accepted: <literal>forever</literal> or <literal>infinity</literal>
+ which is the default and means that the address never expires, and <literal>0</literal> which means
+ that the address is considered immediately "expired" and will not be used,
+ unless explicitly requested. A setting of PreferredLifetime=0 is useful for
+ addresses which are added to be used only by a specific application,
+ which is then configured to use them explicitly.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>HomeAddress=</varname></term>
+ <listitem>
+ <para>Takes a boolean argument. Designates this address the "home address" as defined in
+ <ulink url="https://tools.ietf.org/html/rfc6275">RFC 6275</ulink>.
+ Supported only on IPv6. Defaults to false.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>DuplicateAddressDetection=</varname></term>
+ <listitem>
+ <para>Takes a boolean argument. Do not perform Duplicate Address Detection
+ <ulink url="https://tools.ietf.org/html/rfc4862">RFC 4862</ulink> when adding this address.
+ Supported only on IPv6. Defaults to false.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>ManageTemporaryAddress=</varname></term>
+ <listitem>
+ <para>Takes a boolean argument. If true the kernel manage temporary addresses created
+ from this one as template on behalf of Privacy Extensions
+ <ulink url="https://tools.ietf.org/html/rfc3041">RFC 3041</ulink>. For this to become
+ active, the use_tempaddr sysctl setting has to be set to a value greater than zero.
+ The given address needs to have a prefix length of 64. This flag allows to use privacy
+ extensions in a manually configured network, just like if stateless auto-configuration
+ was active. Defaults to false. </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>PrefixRoute=</varname></term>
+ <listitem>
+ <para>Takes a boolean argument. When adding or modifying an IPv6 address, the userspace
+ application needs a way to suppress adding a prefix route. This is for example relevant
+ together with IFA_F_MANAGERTEMPADDR, where userspace creates autoconf generated addresses,
+ but depending on on-link, no route for the prefix should be added. Defaults to false.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>AutoJoin=</varname></term>
+ <listitem>
+ <para>Takes a boolean argument. Joining multicast group on ethernet level via
+ <command>ip maddr</command> command would not work if we have an Ethernet switch that does
+ IGMP snooping since the switch would not replicate multicast packets on ports that did not
+ have IGMP reports for the multicast addresses. Linux vxlan interfaces created via
+ <command>ip link add vxlan</command> or networkd's netdev kind vxlan have the group option
+ that enables then to do the required join. By extending ip address command with option
+ <literal>autojoin</literal> we can get similar functionality for openvswitch (OVS) vxlan
+ interfaces as well as other tunneling mechanisms that need to receive multicast traffic.
+ Defaults to <literal>no</literal>.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>[Route] Section Options</title>
+ <para>The <literal>[Route]</literal> section accepts the
+ following keys. Specify several <literal>[Route]</literal>
+ sections to configure several routes.</para>
+
+ <variablelist class='network-directives'>
+ <varlistentry>
+ <term><varname>Gateway=</varname></term>
+ <listitem>
+ <para>As in the <literal>[Network]</literal> section.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Destination=</varname></term>
+ <listitem>
+ <para>The destination prefix of the route. Possibly
+ followed by a slash and the prefix length. If omitted, a
+ full-length host route is assumed.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Source=</varname></term>
+ <listitem>
+ <para>The source prefix of the route. Possibly followed by
+ a slash and the prefix length. If omitted, a full-length
+ host route is assumed.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Metric=</varname></term>
+ <listitem>
+ <para>The metric of the route (an unsigned integer).</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Scope=</varname></term>
+ <listitem>
+ <para>The scope of the route, which can be <literal>global</literal>,
+ <literal>link</literal> or <literal>host</literal>. Defaults to
+ <literal>global</literal>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>PreferredSource=</varname></term>
+ <listitem>
+ <para>The preferred source address of the route. The address
+ must be in the format described in
+ <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Table=<replaceable>num</replaceable></varname></term>
+ <listitem>
+ <para>The table identifier for the route (a number between 1 and 4294967295, or 0 to unset).
+ The table can be retrieved using <command>ip route show table <replaceable>num</replaceable></command>.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>[DHCP] Section Options</title>
+ <para>The <literal>[DHCP]</literal> section configures the
+ DHCPv4 and DHCP6 client, if it is enabled with the
+ <varname>DHCP=</varname> setting described above:</para>
+
+ <variablelist class='network-directives'>
+ <varlistentry>
+ <term><varname>UseDNS=</varname></term>
+ <listitem>
+ <para>When true (the default), the DNS servers received
+ from the DHCP server will be used and take precedence over
+ any statically configured ones.</para>
+
+ <para>This corresponds to the <option>nameserver</option>
+ option in <citerefentry
+ project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>UseNTP=</varname></term>
+ <listitem>
+ <para>When true (the default), the NTP servers received
+ from the DHCP server will be used by systemd-timesyncd
+ and take precedence over any statically configured ones.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>UseMTU=</varname></term>
+ <listitem>
+ <para>When true, the interface maximum transmission unit
+ from the DHCP server will be used on the current link.
+ Defaults to false.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>SendHostname=</varname></term>
+ <listitem>
+ <para>When true (the default), the machine's hostname will
+ be sent to the DHCP server.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>UseHostname=</varname></term>
+ <listitem>
+ <para>When true (the default), the hostname received from
+ the DHCP server will be set as the transient hostname of the system
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Hostname=</varname></term>
+ <listitem>
+ <para>Use this value for the hostname which is sent to the
+ DHCP server, instead of machine's hostname.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>UseDomains=</varname></term>
+ <listitem>
+ <para>Takes a boolean argument, or the special value <literal>route</literal>. When true, the domain name
+ received from the DHCP server will be used as DNS search domain over this link, similar to the effect of
+ the <option>Domains=</option> setting. If set to <literal>route</literal>, the domain name received from
+ the DHCP server will be used for routing DNS queries only, but not for searching, similar to the effect of
+ the <option>Domains=</option> setting when the argument is prefixed with <literal>~</literal>. Defaults to
+ false.</para>
+
+ <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
+ of all host names, in particular of single-label names. It is generally safer to use the supplied domain
+ only as routing domain, rather than as search domain, in order to not have it affect local resolution of
+ single-label names.</para>
+
+ <para>When set to true, this setting corresponds to the <option>domain</option> option in <citerefentry
+ project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>UseRoutes=</varname></term>
+ <listitem>
+ <para>When true (the default), the static routes will be
+ requested from the DHCP server and added to the routing
+ table with a metric of 1024.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>UseTimezone=</varname></term>
+
+ <listitem><para>When true, the timezone received from the
+ DHCP server will be set as timezone of the local
+ system. Defaults to <literal>no</literal>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>CriticalConnection=</varname></term>
+ <listitem>
+ <para>When true, the connection will never be torn down
+ even if the DHCP lease expires. This is contrary to the
+ DHCP specification, but may be the best choice if, say,
+ the root filesystem relies on this connection. Defaults to
+ false.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>ClientIdentifier=</varname></term>
+ <listitem>
+ <para>The DHCPv4 client identifier to use. Either <literal>mac</literal> to use the MAC address of the link
+ or <literal>duid</literal> (the default, see below) to use an RFC4361-compliant Client ID.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>VendorClassIdentifier=</varname></term>
+ <listitem>
+ <para>The vendor class identifier used to identify vendor
+ type and configuration.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>DUIDType=</varname></term>
+ <listitem>
+ <para>Override the global <varname>DUIDType</varname> setting for this network. See
+ <citerefentry><refentrytitle>networkd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for a description of possible values.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>DUIDRawData=</varname></term>
+ <listitem>
+ <para>Override the global <varname>DUIDRawData</varname> setting for this network. See
+ <citerefentry><refentrytitle>networkd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for a description of possible values.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>IAID=</varname></term>
+ <listitem>
+ <para>The DHCP Identity Association Identifier (IAID) for the interface, a 32-bit unsigned integer.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>RequestBroadcast=</varname></term>
+ <listitem>
+ <para>Request the server to use broadcast messages before
+ the IP address has been configured. This is necessary for
+ devices that cannot receive RAW packets, or that cannot
+ receive packets at all before an IP address has been
+ configured. On the other hand, this must not be enabled on
+ networks where broadcasts are filtered out.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>RouteMetric=</varname></term>
+ <listitem>
+ <para>Set the routing metric for routes specified by the
+ DHCP server.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>RouteTable=<replaceable>num</replaceable></varname></term>
+ <listitem>
+ <para>The table identifier for DHCP routes (a number between 1 and 4294967295, or 0 to unset).
+ The table can be retrieved using <command>ip route show table <replaceable>num</replaceable></command>.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>[IPv6AcceptRA] Section Options</title>
+ <para>The <literal>[IPv6AcceptRA]</literal> section configures the IPv6 Router Advertisement
+ (RA) client, if it is enabled with the <varname>IPv6AcceptRA=</varname> setting described
+ above:</para>
+
+ <variablelist class='network-directives'>
+ <varlistentry>
+ <term><varname>UseDNS=</varname></term>
+ <listitem>
+ <para>When true (the default), the DNS servers received in the Router Advertisement will be used and take
+ precedence over any statically configured ones.</para>
+
+ <para>This corresponds to the <option>nameserver</option> option in <citerefentry
+ project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>UseDomains=</varname></term>
+ <listitem>
+ <para>Takes a boolean argument, or the special value <literal>route</literal>. When true, the domain name
+ received via IPv6 Router Advertisement (RA) will be used as DNS search domain over this link, similar to
+ the effect of the <option>Domains=</option> setting. If set to <literal>route</literal>, the domain name
+ received via IPv6 RA will be used for routing DNS queries only, but not for searching, similar to the
+ effect of the <option>Domains=</option> setting when the argument is prefixed with
+ <literal>~</literal>. Defaults to false.</para>
+
+ <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
+ of all host names, in particular of single-label names. It is generally safer to use the supplied domain
+ only as routing domain, rather than as search domain, in order to not have it affect local resolution of
+ single-label names.</para>
+
+ <para>When set to true, this setting corresponds to the <option>domain</option> option in <citerefentry
+ project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>RouteTable=<replaceable>num</replaceable></varname></term>
+ <listitem>
+ <para>The table identifier for the routes received in the Router Advertisement
+ (a number between 1 and 4294967295, or 0 to unset).
+ The table can be retrieved using <command>ip route show table <replaceable>num</replaceable></command>.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+
+ <refsect1>
+ <title>[DHCPServer] Section Options</title>
+ <para>The <literal>[DHCPServer]</literal> section contains
+ settings for the DHCP server, if enabled via the
+ <varname>DHCPServer=</varname> option described above:</para>
+
+ <variablelist class='network-directives'>
+
+ <varlistentry>
+ <term><varname>PoolOffset=</varname></term>
+ <term><varname>PoolSize=</varname></term>
+
+ <listitem><para>Configures the pool of addresses to hand out. The pool
+ is a contiguous sequence of IP addresses in the subnet configured for
+ the server address, which does not include the subnet nor the broadcast
+ address. <varname>PoolOffset=</varname> takes the offset of the pool
+ from the start of subnet, or zero to use the default value.
+ <varname>PoolSize=</varname> takes the number of IP addresses in the
+ pool or zero to use the default value. By default, the pool starts at
+ the first address after the subnet address and takes up the rest of
+ the subnet, excluding the broadcast address. If the pool includes
+ the server address (the default), this is reserved and not handed
+ out to clients.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>DefaultLeaseTimeSec=</varname></term>
+ <term><varname>MaxLeaseTimeSec=</varname></term>
+
+ <listitem><para>Control the default and maximum DHCP lease
+ time to pass to clients. These settings take time values in seconds or
+ another common time unit, depending on the suffix. The default
+ lease time is used for clients that did not ask for a specific
+ lease time. If a client asks for a lease time longer than the
+ maximum lease time, it is automatically shortened to the
+ specified time. The default lease time defaults to 1h, the
+ maximum lease time to 12h. Shorter lease times are beneficial
+ if the configuration data in DHCP leases changes frequently
+ and clients shall learn the new settings with shorter
+ latencies. Longer lease times reduce the generated DHCP
+ network traffic.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>EmitDNS=</varname></term>
+ <term><varname>DNS=</varname></term>
+
+ <listitem><para>Configures whether the DHCP leases handed out
+ to clients shall contain DNS server information. The
+ <varname>EmitDNS=</varname> setting takes a boolean argument
+ and defaults to <literal>yes</literal>. The DNS servers to
+ pass to clients may be configured with the
+ <varname>DNS=</varname> option, which takes a list of IPv4
+ addresses. If the <varname>EmitDNS=</varname> option is
+ enabled but no servers configured, the servers are
+ automatically propagated from an "uplink" interface that has
+ appropriate servers set. The "uplink" interface is determined
+ by the default route of the system with the highest
+ priority. Note that this information is acquired at the time
+ the lease is handed out, and does not take uplink interfaces
+ into account that acquire DNS or NTP server information at a
+ later point. DNS server propagation does not take
+ <filename>/etc/resolv.conf</filename> into account. Also, note
+ that the leases are not refreshed if the uplink network
+ configuration changes. To ensure clients regularly acquire the
+ most current uplink DNS server information, it is thus
+ advisable to shorten the DHCP lease time via
+ <varname>MaxLeaseTimeSec=</varname> described
+ above.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>EmitNTP=</varname></term>
+ <term><varname>NTP=</varname></term>
+
+ <listitem><para>Similar to the <varname>EmitDNS=</varname> and
+ <varname>DNS=</varname> settings described above, these
+ settings configure whether and what NTP server information
+ shall be emitted as part of the DHCP lease. The same syntax,
+ propagation semantics and defaults apply as for
+ <varname>EmitDNS=</varname> and
+ <varname>DNS=</varname>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>EmitRouter=</varname></term>
+
+ <listitem><para>Similar to the <varname>EmitDNS=</varname>
+ setting described above, this setting configures whether the
+ DHCP lease should contain the router option. The same syntax,
+ propagation semantics and defaults apply as for
+ <varname>EmitDNS=</varname>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>EmitTimezone=</varname></term>
+ <term><varname>Timezone=</varname></term>
+
+ <listitem><para>Configures whether the DHCP leases handed out
+ to clients shall contain timezone information. The
+ <varname>EmitTimezone=</varname> setting takes a boolean
+ argument and defaults to <literal>yes</literal>. The
+ <varname>Timezone=</varname> setting takes a timezone string
+ (such as <literal>Europe/Berlin</literal> or
+ <literal>UTC</literal>) to pass to clients. If no explicit
+ timezone is set, the system timezone of the local host is
+ propagated, as determined by the
+ <filename>/etc/localtime</filename> symlink.</para></listitem>
+ </varlistentry>
+
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>[Bridge] Section Options</title>
+ <para>The <literal>[Bridge]</literal> section accepts the
+ following keys.</para>
+ <variablelist class='network-directives'>
+ <varlistentry>
+ <term><varname>UnicastFlood=</varname></term>
+ <listitem>
+ <para>A boolean. Controls whether the bridge should flood
+ traffic for which an FDB entry is missing and the destination
+ is unknown through this port. Defaults to on.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>HairPin=</varname></term>
+ <listitem>
+ <para>A boolean. Configures whether traffic may be sent back
+ out of the port on which it was received. By default, this
+ flag is false, and the bridge will not forward traffic back
+ out of the receiving port.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>UseBPDU=</varname></term>
+ <listitem>
+ <para>A boolean. Configures whether STP Bridge Protocol Data Units will be
+ processed by the bridge port. Defaults to yes.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>FastLeave=</varname></term>
+ <listitem>
+ <para>A boolean. This flag allows the bridge to immediately stop multicast
+ traffic on a port that receives an IGMP Leave message. It is only used with
+ IGMP snooping if enabled on the bridge. Defaults to off.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>AllowPortToBeRoot=</varname></term>
+ <listitem>
+ <para>A boolean. Configures whether a given port is allowed to
+ become a root port. Only used when STP is enabled on the bridge.
+ Defaults to on.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Cost=</varname></term>
+ <listitem>
+ <para>Sets the "cost" of sending packets of this interface.
+ Each port in a bridge may have a different speed and the cost
+ is used to decide which link to use. Faster interfaces
+ should have lower costs.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsect1>
+ <title>[BridgeFDB] Section Options</title>
+ <para>The <literal>[BridgeFDB]</literal> section manages the
+ forwarding database table of a port and accepts the following
+ keys. Specify several <literal>[BridgeFDB]</literal> sections to
+ configure several static MAC table entries.</para>
+
+ <variablelist class='network-directives'>
+ <varlistentry>
+ <term><varname>MACAddress=</varname></term>
+ <listitem>
+ <para>As in the <literal>[Network]</literal> section. This
+ key is mandatory.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>VLANId=</varname></term>
+ <listitem>
+ <para>The VLAN ID for the new static MAC table entry. If
+ omitted, no VLAN ID info is appended to the new static MAC
+ table entry.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsect1>
+ <title>[BridgeVLAN] Section Options</title>
+ <para>The <literal>[BridgeVLAN]</literal> section manages the VLAN ID configuration of a bridge port and accepts
+ the following keys. Specify several <literal>[BridgeVLAN]</literal> sections to configure several VLAN entries.
+ The <varname>VLANFiltering=</varname> option has to be enabled, see <literal>[Bridge]</literal> section in
+ <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+
+ <variablelist class='network-directives'>
+ <varlistentry>
+ <term><varname>VLAN=</varname></term>
+ <listitem>
+ <para>The VLAN ID allowed on the port. This can be either a single ID or a range M-N. VLAN IDs are valid
+ from 1 to 4094.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>EgressUntagged=</varname></term>
+ <listitem>
+ <para>The VLAN ID specified here will be used to untag frames on egress. Configuring
+ <varname>EgressUntagged=</varname> implicates the use of <varname>VLAN=</varname> above and will enable the
+ VLAN ID for ingress as well. This can be either a single ID or a range M-N.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>PVID=</varname></term>
+ <listitem>
+ <para>The Port VLAN ID specified here is assigned to all untagged frames at ingress.
+ <varname>PVID=</varname> can be used only once. Configuring <varname>PVID=</varname> implicates the use of
+ <varname>VLAN=</varname> above and will enable the VLAN ID for ingress as well.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Example</title>
+ <example>
+ <title>/etc/systemd/network/50-static.network</title>
+
+ <programlisting>[Match]
+Name=enp2s0
+
+[Network]
+Address=192.168.0.15/24
+Gateway=192.168.0.1</programlisting>
+ </example>
+
+ <example>
+ <title>/etc/systemd/network/80-dhcp.network</title>
+
+ <programlisting>[Match]
+Name=en*
+
+[Network]
+DHCP=yes</programlisting>
+ </example>
+
+ <example>
+ <title>/etc/systemd/network/25-bridge-static.network</title>
+
+ <programlisting>[Match]
+Name=bridge0
+
+[Network]
+Address=192.168.0.15/24
+Gateway=192.168.0.1
+DNS=192.168.0.1</programlisting>
+ </example>
+
+ <example>
+ <title>/etc/systemd/network/25-bridge-slave-interface.network</title>
+
+ <programlisting>[Match]
+Name=enp2s0
+
+[Network]
+Bridge=bridge0</programlisting>
+ </example>
+ <example>
+ <title>/etc/systemd/network/25-bridge-slave-interface-vlan.network</title>
+
+ <programlisting>[Match]
+Name=enp2s0
+
+[Network]
+Bridge=bridge0
+
+[BridgeVLAN]
+VLAN=1-32
+PVID=42
+EgressUntagged=42
+
+[BridgeVLAN]
+VLAN=100-200
+
+[BridgeVLAN]
+EgressUntagged=300-400</programlisting>
+ </example>
+ <example>
+ <title>/etc/systemd/network/25-ipip.network</title>
+
+ <programlisting>[Match]
+Name=em1
+
+[Network]
+Tunnel=ipip-tun</programlisting>
+ </example>
+
+ <example>
+ <title>/etc/systemd/network/25-sit.network</title>
+
+ <programlisting>[Match]
+Name=em1
+
+[Network]
+Tunnel=sit-tun</programlisting>
+ </example>
+
+ <example>
+ <title>/etc/systemd/network/25-gre.network</title>
+
+ <programlisting>[Match]
+Name=em1
+
+[Network]
+Tunnel=gre-tun</programlisting>
+ </example>
+
+ <example>
+ <title>/etc/systemd/network/25-vti.network</title>
+
+ <programlisting>[Match]
+Name=em1
+
+[Network]
+Tunnel=vti-tun</programlisting>
+ </example>
+
+ <example>
+ <title>/etc/systemd/network/25-bond.network</title>
+
+ <programlisting>[Match]
+Name=bond1
+
+[Network]
+DHCP=yes
+</programlisting>
+ </example>
+
+ <example>
+ <title>/etc/systemd/network/25-vrf.network</title>
+ <para>Add the bond1 interface to the VRF master interface vrf-test. This will redirect routes generated on this interface to be within the routing table defined during VRF creation. Traffic won't be redirected towards the VRFs routing table unless specific ip-rules are added.</para>
+ <programlisting>[Match]
+Name=bond1
+
+[Network]
+VRF=vrf-test
+</programlisting>
+ </example>
+
+ </refsect1>
+
+ <refsect1>
+ <title>See Also</title>
+ <para>
+ <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ </para>
+ </refsect1>
+
+</refentry>