3846N/A<?
xml version='1.0'?>
<!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> 3846N/A<!
DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" 3846N/A This file is part of systemd. 3846N/A Copyright 2013 Tom Gundersen 3846N/A systemd is free software; you can redistribute it and/or modify it 3846N/A under the terms of the GNU Lesser General Public License as published by 3846N/A the Free Software Foundation; either version 2.1 of the License, or 3846N/A (at your option) any later version. 3846N/A systemd is distributed in the hope that it will be useful, but 3846N/A WITHOUT ANY WARRANTY; without even the implied warranty of 3846N/A MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 3846N/A Lesser General Public License for more details. 3846N/A You should have received a copy of the GNU Lesser General Public License 3846N/A <
productname>systemd</
productname>
3846N/A <
contrib>Developer</
contrib>
3846N/A <
surname>Gundersen</
surname>
3846N/A <
refpurpose>Network configuration</
refpurpose>
3846N/A <
para><
filename><
replaceable>network</
replaceable>.network</
filename></
para>
3846N/A <
para>Network setup is performed by
3846N/A <
citerefentry><
refentrytitle>systemd-networkd</
refentrytitle><
manvolnum>8</
manvolnum></
citerefentry>.
3846N/A <
para>Network files must have the extension
3846N/A <
filename>.network</
filename>; other extensions are ignored.
3846N/A Networks are applied to links whenever the links appear.</
para>
3846N/A <
para>The <
filename>.network</
filename> files are read from the
3846N/A files located in the system network directory
3846N/A administration network directory
3846N/A are collectively sorted and processed in lexical order, regardless
3846N/A of the directories in which they live. However, files with
3846N/A identical filenames replace each other. Files in
3846N/A <
filename>/etc</
filename> have the highest priority, files in
3846N/A <
filename>/run</
filename> take precedence over files with the same
3846N/A name in <
filename>/
usr/
lib</
filename>. This can be used to
3846N/A override a system-supplied configuration file with a local file if
3846N/A needed. As a special case, an empty file (file size 0) or symlink
3846N/A disables the configuration file entirely (it is "masked").</
para>
3846N/A <
title>[Match] Section Options</
title>
3846N/A <
para>The network file contains a <
literal>[Match]</
literal>
3846N/A section, which determines if a given network file may be applied
3846N/A to a given device; and a <
literal>[Network]</
literal> section
3846N/A specifying how the device should be configured. The first (in
3846N/A lexical order) of the network files that matches a given device
3846N/A is applied, all later files are ignored, even if they match as
3846N/A <
para>A network file is said to match a device if each of the
7168N/A entries in the <
literal>[Match]</
literal> section matches, or if
3846N/A the section is empty. The following keys are accepted:</
para>
3846N/A <
variablelist class='network-directives'>
3846N/A <
term><
varname>MACAddress=</
varname></
term>
3846N/A <
para>The hardware address.</
para>
3846N/A <
term><
varname>Path=</
varname></
term>
3846N/A <
para>A whitespace-separated list of shell-style globs
3846N/A matching the persistent path, as exposed by the udev
3846N/A property <
literal>ID_PATH</
literal>.</
para>
3846N/A <
term><
varname>Driver=</
varname></
term>
3846N/A <
para>A whitespace-separated list of shell-style globs
3846N/A matching the driver currently bound to the device, as
3846N/A exposed by the udev property <
literal>DRIVER</
literal>
3846N/A of its parent device, or if that is not set the driver
3846N/A as exposed by <
literal>ethtool -i</
literal> of the
3846N/A <
term><
varname>Type=</
varname></
term>
3846N/A <
para>A whitespace-separated list of shell-style globs
3846N/A matching the device type, as exposed by the udev property
3846N/A <
literal>DEVTYPE</
literal>.</
para>
3846N/A <
term><
varname>Name=</
varname></
term>
3846N/A <
para>A whitespace-separated list of shell-style globs
3846N/A matching the device name, as exposed by the udev property
3846N/A <
literal>INTERFACE</
literal>.</
para>
3846N/A <
term><
varname>Host=</
varname></
term>
3846N/A <
para>Matches against the hostname or machine ID of the
3846N/A host. See <
literal>ConditionHost=</
literal> in
3846N/A <
citerefentry><
refentrytitle>
systemd.unit</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>
3846N/A <
term><
varname>Virtualization=</
varname></
term>
3846N/A <
para>Checks whether the system is executed in a virtualized
3846N/A environment and optionally test whether it is a specific
3846N/A implementation. See <
literal>ConditionVirtualization=</
literal> in
3846N/A <
citerefentry><
refentrytitle>
systemd.unit</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>
3846N/A <
term><
varname>KernelCommandLine=</
varname></
term>
3846N/A <
para>Checks whether a specific kernel command line option is
3846N/A set (or if prefixed with the exclamation mark unset). See
3846N/A <
literal>ConditionKernelCommandLine=</
literal> in
3846N/A <
citerefentry><
refentrytitle>
systemd.unit</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>
3846N/A <
term><
varname>Architecture=</
varname></
term>
3846N/A <
para>Checks whether the system is running on a specific
3846N/A architecture. See <
literal>ConditionArchitecture=</
literal> in
3846N/A <
citerefentry><
refentrytitle>
systemd.unit</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>
3846N/A <
title>[Link] Section Options</
title>
3846N/A <
para> The <
literal>[Link]</
literal> section accepts the following keys:</
para>
3846N/A <
variablelist class='network-directives'>
3846N/A <
term><
varname>MACAddress=</
varname></
term>
3846N/A <
para>The hardware address.</
para>
3846N/A <
term><
varname>MTUBytes=</
varname></
term>
3846N/A <
para>The maximum transmission unit in bytes to set for the
3846N/A device. The usual suffixes K, M, G, are supported and are
3846N/A understood to the base of 1024.</
para>
3846N/A <
title>[Network] Section Options</
title>
3846N/A <
para>The <
literal>[Network]</
literal> section accepts the following keys:</
para>
3846N/A <
variablelist class='network-directives'>
3846N/A <
term><
varname>Description=</
varname></
term>
3846N/A <
para>A description of the device. This is only used for
3846N/A presentation purposes.</
para>
3846N/A <
term><
varname>DHCP=</
varname></
term>
3846N/A <
para>Enables DHCPv4
and/
or DHCPv6 client support. Accepts
3846N/A <
literal>yes</
literal>, <
literal>no</
literal>,
3846N/A <
literal>ipv4</
literal>, or <
literal>ipv6</
literal>.</
para>
3846N/A <
para>Please note that, by default, the domain name
3846N/A specified through DHCP is not used for name resolution.
3846N/A See option <
option>UseDomains=</
option> below.</
para>
3846N/A <
term><
varname>DHCPServer=</
varname></
term>
3846N/A <
para>A boolean. Enables DHCPv4 server support. Defaults
3846N/A to <
literal>no</
literal>. Further settings for the DHCP
3846N/A server may be set in the <
literal>[DHCPServer]</
literal>
3846N/A section described below.</
para>
3846N/A <
term><
varname>LinkLocalAddressing=</
varname></
term>
3846N/A <
para>Enables link-local address autoconfiguration. Accepts
3846N/A <
literal>yes</
literal>, <
literal>no</
literal>,
3846N/A <
literal>ipv4</
literal>, or <
literal>ipv6</
literal>. Defaults to
3846N/A <
literal>ipv6</
literal>.</
para>
3846N/A <
term><
varname>IPv4LLRoute=</
varname></
term>
3846N/A <
para>A boolean. When true, sets up the route needed for
3846N/A non-IPv4LL hosts to communicate with IPv4LL-only hosts. Defaults
3846N/A <
term><
varname>IPv6Token=</
varname></
term>
3846N/A <
para>An IPv6 address with the top 64 bits unset. When set, indicates the
3846N/A 64-bit interface part of SLAAC IPv6 addresses for this link. By default,
3846N/A it is autogenerated.</
para>
3846N/A <
term><
varname>LLMNR=</
varname></
term>
3846N/A <
para>A boolean or <
literal>resolve</
literal>. When true, enables
3846N/A Link-Local Multicast Name Resolution on the link. When set to
3846N/A <
literal>resolve</
literal>, only resolution is enabled, but not
3846N/A announcement. Defaults to true.</
para>
3846N/A <
term><
varname>LLDP=</
varname></
term>
3846N/A <
para>A boolean. When true, enables LLDP link receive support.
3846N/A <
term><
varname>BindCarrier=</
varname></
term>
3846N/A <
para>A port or a list of ports. When set, controls the
3846N/A behavior of the current interface. When all ports in the list
3846N/A are in an operational down state, the current interface is brought
3846N/A down. When at least one port has carrier, the current interface
3846N/A <
term><
varname>Address=</
varname></
term>
3846N/A <
para>A static IPv4 or IPv6 address and its prefix length,
3846N/A separated by a <
literal>/</
literal> character. Specify
3846N/A this key more than once to configure several addresses.
3846N/A The format of the address must be as described in
3846N/A <
citerefentry project='man-pages'><
refentrytitle>inet_pton</
refentrytitle><
manvolnum>3</
manvolnum></
citerefentry>.
3846N/A This is a short-hand for an [Address] section only
3846N/A containing an Address key (see below). This option may be
3846N/A <
para>If the specified address is 0.0.0.0 (for IPv4) or
3846N/A [::] (for IPv6), a new address range of the requested size
3846N/A is automatically allocated from a system-wide pool of
3846N/A unused ranges. The allocated range is checked against all
3846N/A current network interfaces and all known network
3846N/A configuration files to avoid address range conflicts. The
3846N/A IPv6. This functionality is useful to manage a large
3846N/A number of dynamically created network interfaces with the
3846N/A same network configuration and automatic address range
3846N/A <
term><
varname>Gateway=</
varname></
term>
3846N/A <
para>The gateway address, which must be in the format
3846N/A <
citerefentry project='man-pages'><
refentrytitle>inet_pton</
refentrytitle><
manvolnum>3</
manvolnum></
citerefentry>.
3846N/A This is a short-hand for a [Route] section only containing
3846N/A a Gateway key. This option may be specified more than
3846N/A <
term><
varname>DNS=</
varname></
term>
3846N/A <
para>A DNS server address, which must be in the format
3846N/A <
citerefentry project='man-pages'><
refentrytitle>inet_pton</
refentrytitle><
manvolnum>3</
manvolnum></
citerefentry>.
3846N/A This option may be specified more than once.</
para>
3846N/A <
term><
varname>Domains=</
varname></
term>
7168N/A <
para>The domains used for DNS resolution over this link.</
para>
7168N/A <
term><
varname>NTP=</
varname></
term>
7168N/A <
para>An NTP server address. This option may be specified more than once.</
para>
7168N/A <
term><
varname>IPForward=</
varname></
term>
7168N/A <
listitem><
para>Configures IP forwarding for the network
7168N/A interface. If enabled, incoming packets on the network
7168N/A interface will be forwarded to other interfaces according to
7168N/A the routing table. Takes either a boolean argument, or the
7168N/A values <
literal>ipv4</
literal> or <
literal>ipv6</
literal>,
7168N/A which only enables IP forwarding for the specified address
7168N/A family, or <
literal>kernel</
literal>, which preserves existing sysctl settings.
7168N/A sysctl options of the network interface (see <
ulink 7168N/A for details about sysctl options). Defaults to
7168N/A <
literal>no</
literal>.</
para>
7168N/A <
para>Note: unless this option is turned on, or set to <
literal>kernel</
literal>,
7168N/A no IP forwarding is done on this interface, even if this is
7168N/A globally turned on in the kernel, with the
7168N/A <
term><
varname>IPMasquerade=</
varname></
term>
7168N/A <
listitem><
para>Configures IP masquerading for the network
7168N/A interface. If enabled, packets forwarded from the network
7168N/A interface will be appear as coming from the local host.
7168N/A Takes a boolean argument. Implies
7168N/A <
varname>IPForward=ipv4</
varname>. Defaults to
7168N/A <
literal>no</
literal>.</
para></
listitem>
7168N/A <
term><
varname>IPv6PrivacyExtensions=</
varname></
term>
7168N/A <
listitem><
para>Configures use of stateless temporary
7168N/A addresses that change over time (see <
ulink 3846N/A Privacy Extensions for Stateless Address Autoconfiguration
3846N/A in IPv6). Takes a boolean or the special values
3846N/A <
literal>prefer-public</
literal> and
3846N/A <
literal>kernel</
literal>. When true, enables the privacy
3846N/A extensions and prefers temporary addresses over public
3846N/A addresses. When <
literal>prefer-public</
literal>, enables the
3846N/A privacy extensions, but prefers public addresses over
3846N/A temporary addresses. When false, the privacy extensions
3846N/A remain disabled. When <
literal>kernel</
literal>, the kernel's
3846N/A default setting will be left in place. Defaults to
3846N/A <
literal>no</
literal>.</
para></
listitem>
3846N/A <
term><
varname>IPv6AcceptRouterAdvertisements=</
varname></
term>
3846N/A <
listitem><
para>Force the setting of the <
filename>accept_ra</
filename>
3846N/A (router advertisements) setting for the interface.
3846N/A When unset, the kernel default is used, and router
3846N/A advertisements are accepted only when local forwarding
3846N/A is disabled for that interface.
3846N/A Takes a boolean. If true, router advertisements are
3846N/A accepted, when false, router advertisements are ignored,
3846N/A independently of the local forwarding state.</
para>
3846N/A in the kernel documentation, but note that systemd's
3846N/A setting of <
constant>1</
constant> corresponds to
3846N/A kernel's setting of <
constant>2</
constant>.</
para>
7168N/A <
term><
varname>IPv6DuplicateAddressDetection=</
varname></
term>
7168N/A <
listitem><
para>Configures the amount of IPv6 Duplicate
7168N/A Address Detection (DAD) probes to send. Defaults to unset.
7168N/A <
term><
varname>IPv6HopLimit=</
varname></
term>
7168N/A <
listitem><
para>Configures IPv6 Hop Limit. For each router that
7168N/A forwards the packet, the hop limit is decremented by 1. When the
7168N/A hop limit field reaches zero, the packet is discarded.
7168N/A <
term><
varname>Bridge=</
varname></
term>
7168N/A <
para>The name of the bridge to add the link to.</
para>
7168N/A <
term><
varname>Bond=</
varname></
term>
7168N/A <
para>The name of the bond to add the link to.</
para>
7168N/A <
term><
varname>VLAN=</
varname></
term>
7168N/A <
para>The name of a VLAN to create on the link. This
3846N/A option may be specified more than once.</
para>
3846N/A <
term><
varname>MACVLAN=</
varname></
term>
3846N/A <
para>The name of a MACVLAN to create on the link. This
3846N/A option may be specified more than once.</
para>
3846N/A <
term><
varname>VXLAN=</
varname></
term>
3846N/A <
para>The name of a VXLAN to create on the link. This
3846N/A option may be specified more than once.</
para>
3846N/A <
term><
varname>Tunnel=</
varname></
term>
3846N/A <
para>The name of a Tunnel to create on the link. This
3846N/A option may be specified more than once.</
para>
3846N/A <
title>[Address] Section Options</
title>
3846N/A <
para>An <
literal>[Address]</
literal> section accepts the
3846N/A following keys. Specify several <
literal>[Address]</
literal>
3846N/A sections to configure several addresses.</
para>
3846N/A <
variablelist class='network-directives'>
3846N/A <
term><
varname>Address=</
varname></
term>
3846N/A <
para>As in the <
literal>[Network]</
literal> section. This
3846N/A <
term><
varname>Peer=</
varname></
term>
3846N/A <
para>The peer address in a point-to-point connection.
3846N/A Accepts the same format as the <
literal>Address</
literal>
3846N/A <
term><
varname>Broadcast=</
varname></
term>
3846N/A <
para>The broadcast address, which must be in the format
3846N/A <
citerefentry project='man-pages'><
refentrytitle>inet_pton</
refentrytitle><
manvolnum>3</
manvolnum></
citerefentry>.
3846N/A This key only applies to IPv4 addresses. If it is not
3846N/A given, it is derived from the <
literal>Address</
literal>
3846N/A <
term><
varname>Label=</
varname></
term>
3846N/A <
para>An address label.</
para>
3846N/A <
title>[Route] Section Options</
title>
3846N/A <
para>The <
literal>[Route]</
literal> section accepts the
3846N/A following keys. Specify several <
literal>[Route]</
literal>
3846N/A sections to configure several routes.</
para>
3846N/A <
variablelist class='network-directives'>
3846N/A <
term><
varname>Gateway=</
varname></
term>
7168N/A <
para>As in the <
literal>[Network]</
literal> section.</
para>
3846N/A <
term><
varname>Destination=</
varname></
term>
3846N/A <
para>The destination prefix of the route. Possibly
3846N/A followed by a slash and the prefix length. If omitted, a
3846N/A full-length host route is assumed.</
para>
3846N/A <
term><
varname>Source=</
varname></
term>
3846N/A <
para>The source prefix of the route. Possibly followed by
3846N/A a slash and the prefix length. If omitted, a full-length
3846N/A host route is assumed.</
para>
3846N/A <
term><
varname>Metric=</
varname></
term>
3846N/A <
para>The metric of the route (an unsigned integer).</
para>
3846N/A <
term><
varname>Scope=</
varname></
term>
3846N/A <
para>The scope of the route, which can be <
literal>global</
literal>,
3846N/A <
literal>link</
literal> or <
literal>host</
literal>. Defaults to
3846N/A <
literal>global</
literal>.</
para>
3846N/A <
term><
varname>PreferredSource=</
varname></
term>
3846N/A <
para>The preferred source address of the route. The address
3846N/A must be in the format described in
3846N/A <
citerefentry project='man-pages'><
refentrytitle>inet_pton</
refentrytitle><
manvolnum>3</
manvolnum></
citerefentry>.</
para>
3846N/A <
title>[DHCP] Section Options</
title>
3846N/A <
para>The <
literal>[DHCP]</
literal> section configures the
3846N/A DHCPv4 and DHCP6 client, if it is enabled with the
3846N/A <
varname>DHCP=</
varname> setting described above:</
para>
3846N/A <
variablelist class='network-directives'>
3846N/A <
term><
varname>UseDNS=</
varname></
term>
3846N/A <
para>When true (the default), the DNS servers received
3846N/A from the DHCP server will be used and take precedence over
3846N/A any statically configured ones.</
para>
3846N/A <
para>This corresponds to the <
option>nameserver</
option>
3846N/A project='man-pages'><
refentrytitle>
resolv.conf</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>.</
para>
3846N/A <
term><
varname>UseNTP=</
varname></
term>
3846N/A <
para>When true (the default), the NTP servers received
7168N/A from the DHCP server will be used by systemd-timesyncd
7168N/A and take precedence over any statically configured ones.</
para>
7168N/A <
term><
varname>UseMTU=</
varname></
term>
7168N/A <
para>When true, the interface maximum transmission unit
7168N/A from the DHCP server will be used on the current link.
7168N/A <
term><
varname>SendHostname=</
varname></
term>
7168N/A <
para>When true (the default), the machine's hostname will
7168N/A be sent to the DHCP server.</
para>
3846N/A <
term><
varname>UseHostname=</
varname></
term>
3846N/A <
para>When true (the default), the hostname received from
3846N/A the DHCP server will be set as the transient hostname of the system
3846N/A <
term><
varname>Hostname=</
varname></
term>
3846N/A <
para>Use this value for the hostname which is sent to the
3846N/A DHCP server, instead of machine's hostname.</
para>
3846N/A <
term><
varname>UseDomains=</
varname></
term>
3846N/A <
para>When true (not the default), the domain name
3846N/A received from the DHCP server will be used for DNS
3846N/A resolution over this link. When a name cannot be resolved
3846N/A as specified, the domain name will be used a suffix and
3846N/A name resolution of that will be attempted.</
para>
3846N/A <
para>This corresponds to the <
option>domain</
option>
3846N/A option in <
citerefentry project='man-pages'><
refentrytitle>
resolv.conf</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>
3846N/A and should not be enabled on untrusted networks.</
para>
3846N/A <
term><
varname>UseRoutes=</
varname></
term>
3846N/A <
para>When true (the default), the static routes will be
3846N/A requested from the DHCP server and added to the routing
3846N/A table with a metric of 1024.</
para>
3846N/A <
term><
varname>UseTimezone=</
varname></
term>
3846N/A <
listitem><
para>When true, the timezone received from the
3846N/A DHCP server will be set as as timezone of the local
3846N/A system. Defaults to <
literal>no</
literal>.</
para></
listitem>
3846N/A <
term><
varname>CriticalConnection=</
varname></
term>
3846N/A <
para>When true, the connection will never be torn down
3846N/A even if the DHCP lease expires. This is contrary to the
3846N/A DHCP specification, but may be the best choice if, say,
3846N/A the root filesystem relies on this connection. Defaults to
3846N/A <
term><
varname>ClientIdentifier=</
varname></
term>
3846N/A <
para>DHCP client identifier to use. Either <
literal>mac</
literal>
3846N/A to use the MAC address of the link or <
literal>duid</
literal>
3846N/A (the default) to use a RFC4361-compliant Client ID.</
para>
3846N/A <
term><
varname>VendorClassIdentifier=</
varname></
term>
3846N/A <
para>The vendor class identifier used to identify vendor
3846N/A type and configuration.</
para>
3846N/A <
term><
varname>RequestBroadcast=</
varname></
term>
3846N/A <
para>Request the server to use broadcast messages before
3846N/A the IP address has been configured. This is necessary for
3846N/A devices that cannot receive RAW packets, or that cannot
3846N/A receive packets at all before an IP address has been
3846N/A configured. On the other hand, this must not be enabled on
3846N/A networks where broadcasts are filtered out.</
para>
3846N/A <
term><
varname>RouteMetric=</
varname></
term>
3846N/A <
para>Set the routing metric for routes specified by the
3846N/A <
title>[DHCPServer] Section Options</
title>
3846N/A <
para>The <
literal>[DHCPServer]</
literal> section contains
3846N/A settings for the DHCP server, if enabled via the
3846N/A <
varname>DHCPServer=</
varname> option described above:</
para>
3846N/A <
variablelist class='network-directives'>
3846N/A <
term><
varname>PoolOffset=</
varname></
term>
3846N/A <
term><
varname>PoolSize=</
varname></
term>
3846N/A <
listitem><
para>Configures the pool of addresses to hand out. The pool
3846N/A is a contiguous sequence of IP addresses in the subnet configured for
3846N/A the server address, which does not include the subnet nor the broadcast
3846N/A address. <
varname>PoolOffset=</
varname> takes the offset of the pool
3846N/A from the start of subnet, or zero to use the default value.
3846N/A <
varname>PoolSize=</
varname> takes the number of IP addresses in the
3846N/A pool or zero to use the default value. By default, the pool starts at
3846N/A the first address after the subnet address and takes up the rest of
3846N/A the subnet, excluding the broadcast address. If the pool includes
3846N/A the server address (the default), this is reserved and not handed
3846N/A out to clients.</
para></
listitem>
3846N/A <
term><
varname>DefaultLeaseTimeSec=</
varname></
term>
3846N/A <
term><
varname>MaxLeaseTimeSec=</
varname></
term>
3846N/A <
listitem><
para>Control the default and maximum DHCP lease
3846N/A time to pass to clients. These settings take time values in seconds or
3846N/A another common time unit, depending on the suffix. The default
3846N/A lease time is used for clients that did not ask for a specific
3846N/A lease time. If a client asks for a lease time longer than the
3846N/A maximum lease time, it is automatically shortened to the
3846N/A specified time. The default lease time defaults to 1h, the
3846N/A maximum lease time to 12h. Shorter lease times are beneficial
3846N/A if the configuration data in DHCP leases changes frequently
3846N/A and clients shall learn the new settings with shorter
3846N/A latencies. Longer lease times reduce the generated DHCP
3846N/A network traffic.</
para></
listitem>
3846N/A <
term><
varname>EmitDNS=</
varname></
term>
3846N/A <
term><
varname>DNS=</
varname></
term>
3846N/A <
listitem><
para>Configures whether the DHCP leases handed out
3846N/A to clients shall contain DNS server information. The
3846N/A <
varname>EmitDNS=</
varname> setting takes a boolean argument
3846N/A and defaults to <
literal>yes</
literal>. The DNS servers to
3846N/A pass to clients may be configured with the
3846N/A <
varname>DNS=</
varname> option, which takes a list of IPv4
3846N/A addresses. If the <
varname>EmitDNS=</
varname> option is
3846N/A enabled but no servers configured, the servers are
3846N/A automatically propagated from an "uplink" interface that has
3846N/A appropriate servers set. The "uplink" interface is determined
3846N/A by the default route of the system with the highest
3846N/A priority. Note that this information is acquired at the time
3846N/A the lease is handed out, and does not take uplink interfaces
3846N/A into account that acquire DNS or NTP server information at a
3846N/A later point. DNS server propagation does not take
3846N/A that the leases are not refreshed if the uplink network
3846N/A configuration changes. To ensure clients regularly acquire the
3846N/A most current uplink DNS server information, it is thus
3846N/A advisable to shorten the DHCP lease time via
3846N/A <
varname>MaxLeaseTimeSec=</
varname> described
3846N/A <
term><
varname>EmitNTP=</
varname></
term>
3846N/A <
term><
varname>NTP=</
varname></
term>
3846N/A <
listitem><
para>Similar to the <
varname>EmitDNS=</
varname> and
3846N/A <
varname>DNS=</
varname> settings described above, these
3846N/A settings configure whether and what NTP server information
3846N/A shall be emitted as part of the DHCP lease. The same syntax,
3846N/A propagation semantics and defaults apply as for
3846N/A <
varname>EmitDNS=</
varname> and
3846N/A <
varname>DNS=</
varname>.</
para></
listitem>
3846N/A <
term><
varname>EmitTimezone=</
varname></
term>
3846N/A <
term><
varname>Timezone=</
varname></
term>
3846N/A <
listitem><
para>Configures whether the DHCP leases handed out
3846N/A to clients shall contain timezone information. The
3846N/A <
varname>EmitTimezone=</
varname> setting takes a boolean
3846N/A argument and defaults to <
literal>yes</
literal>. The
3846N/A <
varname>Timezone=</
varname> setting takes a timezone string
3846N/A <
literal>UTC</
literal>) to pass to clients. If no explicit
3846N/A timezone is set, the system timezone of the local host is
3846N/A propagated, as determined by the
3846N/A <
title>[Bridge] Section Options</
title>
3846N/A <
para>The <
literal>[Bridge]</
literal> section accepts the
3846N/A <
variablelist class='network-directives'>
3846N/A <
term><
varname>UnicastFlood=</
varname></
term>
3846N/A <
para>A boolean. Controls whether the bridge should flood
7168N/A traffic for which an FDB entry is missing and the destination
3846N/A is unknown through this port. Defaults to on.
3846N/A <
term><
varname>HairPin=</
varname></
term>
3846N/A <
para>A boolean. Configures whether traffic may be sent back
3846N/A out of the port on which it was received. By default, this
3846N/A flag is false, and the bridge will not forward traffic back
4765N/A out of the receiving port.</
para>
3846N/A <
term><
varname>UseBPDU=</
varname></
term>
7168N/A <
para>A boolean. Configures whether STP Bridge Protocol Data Units will be
3846N/A processed by the bridge port. Defaults to yes.</
para>
3846N/A <
term><
varname>FastLeave=</
varname></
term>
3846N/A <
para>A boolean. This flag allows the bridge to immediately stop multicast
3846N/A traffic on a port that receives an IGMP Leave message. It is only used with
3846N/A IGMP snooping if enabled on the bridge. Defaults to off.</
para>
3846N/A <
term><
varname>AllowPortToBeRoot=</
varname></
term>
3846N/A <
para>A boolean. Configures whether a given port is allowed to
3846N/A become a root port. Only used when STP is enabled on the bridge.
3846N/A <
term><
varname>Cost=</
varname></
term>
3846N/A <
para>Sets the "cost" of sending packets of this interface.
3846N/A Each port in a bridge may have a different speed and the cost
3846N/A is used to decide which link to use. Faster interfaces
3846N/A should have lower costs.</
para>
3846N/A <
title>[BridgeFDB] Section Options</
title>
3846N/A <
para>The <
literal>[BridgeFDB]</
literal> section manages the
3846N/A forwarding database table of a port and accepts the following
3846N/A keys. Specify several <
literal>[BridgeFDB]</
literal> sections to
3846N/A configure several static MAC table entries.</
para>
3846N/A <
variablelist class='network-directives'>
3846N/A <
term><
varname>MACAddress=</
varname></
term>
3846N/A <
para>As in the <
literal>[Network]</
literal> section. This
<
term><
varname>VLANId=</
varname></
term>
<
para>The VLAN ID for the new static MAC table entry. If
omitted, no VLAN ID info is appended to the new static MAC
Gateway=192.168.0.1</
programlisting>
DHCP=yes</
programlisting>
DNS=192.168.0.1</
programlisting>
Bridge=bridge0</
programlisting>
Tunnel=ipip-tun</
programlisting>
Tunnel=sit-tun</
programlisting>
Tunnel=gre-tun</
programlisting>
Tunnel=vti-tun</
programlisting>
<
citerefentry><
refentrytitle>systemd</
refentrytitle><
manvolnum>1</
manvolnum></
citerefentry>,
<
citerefentry><
refentrytitle>systemd-networkd</
refentrytitle><
manvolnum>8</
manvolnum></
citerefentry>,
<
citerefentry><
refentrytitle>
systemd.link</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>,
<
citerefentry><
refentrytitle>
systemd.netdev</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>