man/systemd.network.xml

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  23
  24 <refentry id="systemd.network" conditional='ENABLE_NETWORKD'>
  25
  26   <refentryinfo>
  27     <title>systemd.network</title>
  28     <productname>systemd</productname>
  29
  30     <authorgroup>
  31       <author>
  32         <contrib>Developer</contrib>
  33         <firstname>Tom</firstname>
  34         <surname>Gundersen</surname>
  35         <email>teg@jklm.no</email>
  36       </author>
  37     </authorgroup>
  38   </refentryinfo>
  39
  40   <refmeta>
  41     <refentrytitle>systemd.network</refentrytitle>
  42     <manvolnum>5</manvolnum>
  43   </refmeta>
  44
  45   <refnamediv>
  46     <refname>systemd.network</refname>
  47     <refpurpose>Network configuration</refpurpose>
  48   </refnamediv>
  49
  50   <refsynopsisdiv>
  51     <para><filename><replaceable>network</replaceable>.network</filename></para>
  52   </refsynopsisdiv>
  53
  54   <refsect1>
  55     <title>Description</title>
  56
  57     <para>Network setup is performed by
  58     <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
  59     </para>
  60
  61     <para>Network files must have the extension
  62     <filename>.network</filename>; other extensions are ignored.
  63     Networks are applied to links whenever the links appear.</para>
  64
  65     <para>The <filename>.network</filename> files are read from the
  66     files located in the system network directory
  67     <filename>/usr/lib/systemd/network</filename>, the volatile
  68     runtime network directory
  69     <filename>/run/systemd/network</filename> and the local
  70     administration network directory
  71     <filename>/etc/systemd/network</filename>. All configuration files
  72     are collectively sorted and processed in lexical order, regardless
  73     of the directories in which they live. However, files with
  74     identical filenames replace each other. Files in
  75     <filename>/etc</filename> have the highest priority, files in
  76     <filename>/run</filename> take precedence over files with the same
  77     name in <filename>/usr/lib</filename>. This can be used to
  78     override a system-supplied configuration file with a local file if
  79     needed. As a special case, an empty file (file size 0) or symlink
  80     with the same name pointing to <filename>/dev/null</filename>
  81     disables the configuration file entirely (it is "masked").</para>
  82
  83     <para>Note that an interface without any static IPv6 addresses configured, and neither DHCPv6 nor IPv6LL enabled,
  84     shall be considered to have no IPv6 support. IPv6 will be automatically disabled for that interface by writing "1"
  85     to <filename>/proc/sys/net/ipv6/conf/<replaceable>ifname</replaceable>/disable_ipv6</filename>.
  86     </para>
  87   </refsect1>
  88
  89   <refsect1>
  90     <title>[Match] Section Options</title>
  91
  92       <para>The network file contains a <literal>[Match]</literal>
  93       section, which determines if a given network file may be applied
  94       to a given device; and a <literal>[Network]</literal> section
  95       specifying how the device should be configured. The first (in
  96       lexical order) of the network files that matches a given device
  97       is applied, all later files are ignored, even if they match as
  98       well.</para>
  99
 100       <para>A network file is said to match a device if each of the
 101       entries in the <literal>[Match]</literal> section matches, or if
 102       the section is empty. The following keys are accepted:</para>
 103
 104       <variablelist class='network-directives'>
 105         <varlistentry>
 106           <term><varname>MACAddress=</varname></term>
 107           <listitem>
 108             <para>The hardware address of the interface (use full colon-delimited hexadecimal, e.g.,
 109             01:23:45:67:89:ab).</para>
 110           </listitem>
 111         </varlistentry>
 112         <varlistentry>
 113           <term><varname>Path=</varname></term>
 114           <listitem>
 115             <para>A whitespace-separated list of shell-style globs
 116             matching the persistent path, as exposed by the udev
 117             property <literal>ID_PATH</literal>.</para>
 118           </listitem>
 119         </varlistentry>
 120         <varlistentry>
 121           <term><varname>Driver=</varname></term>
 122           <listitem>
 123             <para>A whitespace-separated list of shell-style globs
 124             matching the driver currently bound to the device, as
 125             exposed by the udev property <literal>DRIVER</literal>
 126             of its parent device, or if that is not set the driver
 127             as exposed by <literal>ethtool -i</literal> of the
 128             device itself.</para>
 129           </listitem>
 130         </varlistentry>
 131         <varlistentry>
 132           <term><varname>Type=</varname></term>
 133           <listitem>
 134             <para>A whitespace-separated list of shell-style globs
 135             matching the device type, as exposed by the udev property
 136             <literal>DEVTYPE</literal>.</para>
 137           </listitem>
 138         </varlistentry>
 139         <varlistentry>
 140           <term><varname>Name=</varname></term>
 141           <listitem>
 142             <para>A whitespace-separated list of shell-style globs
 143             matching the device name, as exposed by the udev property
 144             <literal>INTERFACE</literal>.</para>
 145           </listitem>
 146         </varlistentry>
 147         <varlistentry>
 148           <term><varname>Host=</varname></term>
 149           <listitem>
 150             <para>Matches against the hostname or machine ID of the
 151             host. See <literal>ConditionHost=</literal> in
 152             <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 153             for details.
 154             </para>
 155           </listitem>
 156         </varlistentry>
 157         <varlistentry>
 158           <term><varname>Virtualization=</varname></term>
 159           <listitem>
 160             <para>Checks whether the system is executed in a virtualized
 161             environment and optionally test whether it is a specific
 162             implementation. See <literal>ConditionVirtualization=</literal> in
 163             <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 164             for details.
 165             </para>
 166           </listitem>
 167         </varlistentry>
 168         <varlistentry>
 169           <term><varname>KernelCommandLine=</varname></term>
 170           <listitem>
 171             <para>Checks whether a specific kernel command line option is
 172             set (or if prefixed with the exclamation mark unset). See
 173             <literal>ConditionKernelCommandLine=</literal> in
 174             <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 175             for details.
 176             </para>
 177           </listitem>
 178         </varlistentry>
 179         <varlistentry>
 180           <term><varname>Architecture=</varname></term>
 181           <listitem>
 182             <para>Checks whether the system is running on a specific
 183             architecture. See <literal>ConditionArchitecture=</literal> in
 184             <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 185             for details.
 186             </para>
 187           </listitem>
 188         </varlistentry>
 189       </variablelist>
 190
 191   </refsect1>
 192
 193   <refsect1>
 194     <title>[Link] Section Options</title>
 195
 196     <para> The <literal>[Link]</literal> section accepts the following keys:</para>
 197
 198     <variablelist class='network-directives'>
 199       <varlistentry>
 200         <term><varname>MACAddress=</varname></term>
 201         <listitem>
 202           <para>The hardware address to set for the device.</para>
 203         </listitem>
 204       </varlistentry>
 205       <varlistentry>
 206         <term><varname>MTUBytes=</varname></term>
 207         <listitem>
 208           <para>The maximum transmission unit in bytes to set for the
 209           device. The usual suffixes K, M, G, are supported and are
 210           understood to the base of 1024.</para>
 211           <para>Note that if IPv6 is enabled on the interface, and the MTU is chosen
 212           below 1280 (the minimum MTU for IPv6) it will automatically be increased to this value.</para>
 213         </listitem>
 214       </varlistentry>
 215     </variablelist>
 216   </refsect1>
 217
 218   <refsect1>
 219     <title>[Network] Section Options</title>
 220
 221       <para>The <literal>[Network]</literal> section accepts the following keys:</para>
 222
 223       <variablelist class='network-directives'>
 224         <varlistentry>
 225           <term><varname>Description=</varname></term>
 226           <listitem>
 227             <para>A description of the device. This is only used for
 228             presentation purposes.</para>
 229           </listitem>
 230         </varlistentry>
 231         <varlistentry>
 232           <term><varname>DHCP=</varname></term>
 233           <listitem>
 234             <para>Enables DHCPv4 and/or DHCPv6 client support. Accepts
 235             <literal>yes</literal>, <literal>no</literal>,
 236             <literal>ipv4</literal>, or <literal>ipv6</literal>.</para>
 237
 238             <para>Note that DHCPv6 will by default be triggered by Router
 239             Advertisement, if that is enabled, regardless of this parameter.
 240             By enabling DHCPv6 support explicitly, the DHCPv6 client will
 241             be started regardless of the presence of routers on the link,
 242             or what flags the routers pass. See
 243             <literal>IPv6AcceptRouterAdvertisements=</literal>.</para>
 244
 245             <para>Furthermore, note that by default the domain name
 246             specified through DHCP is not used for name resolution.
 247             See option <option>UseDomains=</option> below.</para>
 248
 249             <para>See the <literal>[DHCP]</literal> section below for further configuration options for the DHCP client
 250             support.</para>
 251           </listitem>
 252         </varlistentry>
 253         <varlistentry>
 254           <term><varname>DHCPServer=</varname></term>
 255           <listitem>
 256             <para>A boolean. Enables DHCPv4 server support. Defaults
 257             to <literal>no</literal>. Further settings for the DHCP
 258             server may be set in the <literal>[DHCPServer]</literal>
 259             section described below.</para>
 260           </listitem>
 261         </varlistentry>
 262         <varlistentry>
 263           <term><varname>LinkLocalAddressing=</varname></term>
 264           <listitem>
 265             <para>Enables link-local address autoconfiguration. Accepts
 266             <literal>yes</literal>, <literal>no</literal>,
 267             <literal>ipv4</literal>, or <literal>ipv6</literal>. Defaults to
 268             <literal>ipv6</literal>.</para>
 269           </listitem>
 270         </varlistentry>
 271         <varlistentry>
 272           <term><varname>IPv4LLRoute=</varname></term>
 273           <listitem>
 274             <para>A boolean. When true, sets up the route needed for
 275             non-IPv4LL hosts to communicate with IPv4LL-only hosts. Defaults
 276             to false.
 277             </para>
 278           </listitem>
 279         </varlistentry>
 280         <varlistentry>
 281           <term><varname>IPv6Token=</varname></term>
 282           <listitem>
 283             <para>An IPv6 address with the top 64 bits unset. When set, indicates the
 284             64-bit interface part of SLAAC IPv6 addresses for this link. Note that
 285             the token is only ever used for SLAAC, and not for DHCPv6 addresses, even
 286             in the case DHCP is requested by router advertisement. By default, the
 287             token is autogenerated.</para>
 288           </listitem>
 289         </varlistentry>
 290         <varlistentry>
 291           <term><varname>LLMNR=</varname></term>
 292           <listitem>
 293             <para>A boolean or <literal>resolve</literal>. When true,
 294             enables <ulink
 295             url="https://tools.ietf.org/html/rfc4795">Link-Local
 296             Multicast Name Resolution</ulink> on the link. When set to
 297             <literal>resolve</literal>, only resolution is enabled,
 298             but not host registration and announcement. Defaults to
 299             true. This setting is read by
 300             <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
 301           </listitem>
 302         </varlistentry>
 303         <varlistentry>
 304           <term><varname>MulticastDNS=</varname></term>
 305           <listitem>
 306             <para>A boolean or <literal>resolve</literal>. When true,
 307             enables <ulink
 308             url="https://tools.ietf.org/html/rfc6762">Multicast
 309             DNS</ulink> support on the link. When set to
 310             <literal>resolve</literal>, only resolution is enabled,
 311             but not host or service registration and
 312             announcement. Defaults to false. This setting is read by
 313             <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
 314           </listitem>
 315         </varlistentry>
 316         <varlistentry>
 317           <term><varname>DNSSEC=</varname></term>
 318           <listitem>
 319             <para>A boolean or
 320             <literal>allow-downgrade</literal>. When true, enables
 321             <ulink
 322             url="https://tools.ietf.org/html/rfc4033">DNSSEC</ulink>
 323             DNS validation support on the link. When set to
 324             <literal>allow-downgrade</literal>, compatibility with
 325             non-DNSSEC capable networks is increased, by automatically
 326             turning off DNSEC in this case. This option defines a
 327             per-interface setting for
 328             <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s
 329             global <varname>DNSSEC=</varname> option. Defaults to
 330             false. This setting is read by
 331             <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
 332           </listitem>
 333         </varlistentry>
 334         <varlistentry>
 335           <term><varname>DNSSECNegativeTrustAnchors=</varname></term>
 336           <listitem><para>A space-separated list of DNSSEC negative
 337           trust anchor domains. If specified and DNSSEC is enabled,
 338           look-ups done via the interface's DNS server will be subject
 339           to the list of negative trust anchors, and not require
 340           authentication for the specified domains, or anything below
 341           it. Use this to disable DNSSEC authentication for specific
 342           private domains, that cannot be proven valid using the
 343           Internet DNS hierarchy. Defaults to the empty list. This
 344           setting is read by
 345           <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
 346           </listitem>
 347         </varlistentry>
 348         <varlistentry>
 349           <term><varname>LLDP=</varname></term>
 350           <listitem>
 351             <para>Controls support for Ethernet LLDP packet reception. LLDP is a link-layer protocol commonly
 352             implemented on professional routers and bridges which announces which physical port a system is connected
 353             to, as well as other related data. Accepts a boolean or the special value
 354             <literal>routers-only</literal>. When true, incoming LLDP packets are accepted and a database of all LLDP
 355             neighbors maintained. If <literal>routers-only</literal> is set only LLDP data of various types of routers
 356             is collected and LLDP data about other types of devices ignored (such as stations, telephones and
 357             others). If false, LLDP reception is disabled. Defaults to <literal>routers-only</literal>. Use
 358             <citerefentry><refentrytitle>networkctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> to query the
 359             collected neighbor data. LLDP is only available on Ethernet links. See <varname>EmitLLDP=</varname> below
 360             for enabling LLDP packet emission from the local system.
 361             </para>
 362           </listitem>
 363         </varlistentry>
 364         <varlistentry>
 365           <term><varname>EmitLLDP=</varname></term>
 366           <listitem>
 367             <para>Controls support for Ethernet LLDP packet emission. Accepts a boolean parameter or the special values
 368             <literal>nearest-bridge</literal>, <literal>non-tpmr-bridge</literal> and
 369             <literal>customer-bridge</literal>.  Defaults to false, which turns off LLDP packet emission. If not false,
 370             a short LLDP packet with information about the local system is sent out in regular intervals on the
 371             link. The LLDP packet will contain information about the local host name, the local machine ID (as stored
 372             in <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>) and the
 373             local interface name, as well as the pretty hostname of the system (as set in
 374             <citerefentry><refentrytitle>machine-info</refentrytitle><manvolnum>5</manvolnum></citerefentry>). LLDP
 375             emission is only available on Ethernet links. Note that this setting passes data suitable for
 376             identification of host to the network and should thus not be enabled on untrusted networks, where such
 377             identification data should not be made available. Use this option to permit other systems to identify on
 378             which interfaces they are connected to this system. The three special values control propagation of the
 379             LLDP packets. The <literal>nearest-bridge</literal> setting permits propagation only to the nearest
 380             connected bridge, <literal>non-tpmr-bridge</literal> permits propagation across Two-Port MAC Relays, but
 381             not any other bridges, and <literal>customer-bridge</literal> permits propagation until a customer bridge
 382             is reached. For details about these concepts, see <ulink
 383             url="http://standards.ieee.org/getieee802/download/802.1AB-2009.pdf">IEEE 802.1AB-2009</ulink>. Note that
 384             configuring this setting to true is equivalent to <literal>nearest-bridge</literal>, the recommended and
 385             most restricted level of propagation. See <varname>LLDP=</varname> above for an option to enable LLDP
 386             reception.</para>
 387           </listitem>
 388         </varlistentry>
 389         <varlistentry>
 390           <term><varname>BindCarrier=</varname></term>
 391           <listitem>
 392             <para>A link name or a list of link names. When set, controls the behavior of the current
 393             link. When all links in the list are in an operational down state, the current link is brought
 394             down. When at least one link has carrier, the current interface is brought up.
 395             </para>
 396           </listitem>
 397         </varlistentry>
 398         <varlistentry>
 399           <term><varname>Address=</varname></term>
 400           <listitem>
 401             <para>A static IPv4 or IPv6 address and its prefix length,
 402             separated by a <literal>/</literal> character. Specify
 403             this key more than once to configure several addresses.
 404             The format of the address must be as described in
 405             <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 406             This is a short-hand for an [Address] section only
 407             containing an Address key (see below). This option may be
 408             specified more than once.
 409             </para>
 410
 411             <para>If the specified address is 0.0.0.0 (for IPv4) or
 412             [::] (for IPv6), a new address range of the requested size
 413             is automatically allocated from a system-wide pool of
 414             unused ranges. The allocated range is checked against all
 415             current network interfaces and all known network
 416             configuration files to avoid address range conflicts. The
 417             default system-wide pool consists of 192.168.0.0/16,
 418             172.16.0.0/12 and 10.0.0.0/8 for IPv4, and fc00::/7 for
 419             IPv6. This functionality is useful to manage a large
 420             number of dynamically created network interfaces with the
 421             same network configuration and automatic address range
 422             assignment.</para>
 423
 424           </listitem>
 425         </varlistentry>
 426         <varlistentry>
 427           <term><varname>Gateway=</varname></term>
 428           <listitem>
 429             <para>The gateway address, which must be in the format
 430             described in
 431             <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 432             This is a short-hand for a [Route] section only containing
 433             a Gateway key. This option may be specified more than
 434             once.</para>
 435           </listitem>
 436         </varlistentry>
 437         <varlistentry>
 438           <term><varname>DNS=</varname></term>
 439           <listitem>
 440             <para>A DNS server address, which must be in the format
 441             described in
 442             <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 443             This option may be specified more than once. This setting is read by
 444             <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
 445           </listitem>
 446         </varlistentry>
 447         <varlistentry>
 448           <term><varname>Domains=</varname></term>
 449           <listitem>
 450             <para>The domains used for DNS host name resolution on this link. Takes a list of DNS domain names which
 451             are used as search suffixes for extending single-label host names (host names containing no dots) to become
 452             fully qualified domain names (FQDNs). If a single-label host name is resolved on this interface, each of
 453             the specified search domains are appended to it in turn, converting it into a fully qualified domain name,
 454             until one of them may be successfully resolved.</para>
 455
 456             <para>The specified domains are also used for routing of DNS queries: look-ups for host names ending in the
 457             domains specified here are preferably routed to the DNS servers configured for this interface. If a domain
 458             name is prefixed with <literal>~</literal>, the domain name becomes a pure "routing" domain, is used for
 459             DNS query routing purposes only and is not used in the described domain search logic. By specifying a
 460             routing domain of <literal>~.</literal> (the tilde indicating definition of a routing domain, the dot
 461             referring to the DNS root domain which is the implied suffix of all valid DNS names) it is possible to
 462             route all DNS traffic preferably to the DNS server specified for this interface. The route domain logic is
 463             particularly useful on multi-homed hosts with DNS servers serving particular private DNS zones on each
 464             interface.</para>
 465
 466             <para>This setting is read by
 467             <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
 468           </listitem>
 469         </varlistentry>
 470         <varlistentry>
 471           <term><varname>NTP=</varname></term>
 472           <listitem>
 473             <para>An NTP server address. This option may be specified more than once. This setting is read by
 474             <citerefentry><refentrytitle>systemd-timesyncd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
 475           </listitem>
 476         </varlistentry>
 477         <varlistentry>
 478           <term><varname>IPForward=</varname></term>
 479           <listitem><para>Configures IP packet forwarding for the
 480           system. If enabled, incoming packets on any network
 481           interface will be forwarded to any other interfaces
 482           according to the routing table. Takes either a boolean
 483           argument, or the values <literal>ipv4</literal> or
 484           <literal>ipv6</literal>, which only enable IP packet
 485           forwarding for the specified address family.  This controls
 486           the <filename>net.ipv4.ip_forward</filename> and
 487           <filename>net.ipv6.conf.all.forwarding</filename> sysctl
 488           options of the network interface (see <ulink
 489           url="https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt</ulink>
 490           for details about sysctl options). Defaults to
 491           <literal>no</literal>.</para>
 492
 493           <para>Note: this setting controls a global kernel option,
 494           and does so one way only: if a network that has this setting
 495           enabled is set up the global setting is turned on.  However,
 496           it is never turned off again, even after all networks with
 497           this setting enabled are shut down again.</para>
 498
 499           <para>To allow IP packet forwarding only between specific
 500           network interfaces use a firewall.</para>
 501           </listitem>
 502         </varlistentry>
 503         <varlistentry>
 504           <term><varname>IPMasquerade=</varname></term>
 505           <listitem><para>Configures IP masquerading for the network
 506           interface. If enabled, packets forwarded from the network
 507           interface will be appear as coming from the local host.
 508           Takes a boolean argument. Implies
 509           <varname>IPForward=ipv4</varname>. Defaults to
 510           <literal>no</literal>.</para></listitem>
 511         </varlistentry>
 512         <varlistentry>
 513           <term><varname>IPv6PrivacyExtensions=</varname></term>
 514           <listitem><para>Configures use of stateless temporary
 515           addresses that change over time (see <ulink
 516           url="https://tools.ietf.org/html/rfc4941">RFC 4941</ulink>,
 517           Privacy Extensions for Stateless Address Autoconfiguration
 518           in IPv6). Takes a boolean or the special values
 519           <literal>prefer-public</literal> and
 520           <literal>kernel</literal>. When true, enables the privacy
 521           extensions and prefers temporary addresses over public
 522           addresses. When <literal>prefer-public</literal>, enables the
 523           privacy extensions, but prefers public addresses over
 524           temporary addresses. When false, the privacy extensions
 525           remain disabled. When <literal>kernel</literal>, the kernel's
 526           default setting will be left in place.  Defaults to
 527           <literal>no</literal>.</para></listitem>
 528         </varlistentry>
 529         <varlistentry>
 530           <term><varname>IPv6AcceptRouterAdvertisements=</varname></term>
 531           <listitem><para>Enable or disable IPv6 Router Advertisement (RA) reception support for the interface.  Takes
 532           a boolean parameter. If true, RAs are accepted; if false, RAs are ignored, independently of the local
 533           forwarding state. When not set, the kernel default is used, and RAs are accepted only when local forwarding
 534           is disabled for that interface.  When RAs are accepted, they may trigger the start of the DHCPv6 client if
 535           the relevant flags are set in the RA data, or if no routers are found on the link.</para>
 536
 537           <para>Further settings for the IPv6 RA support may be configured in the
 538           <literal>[IPv6AcceptRouterAdvertisements]</literal> section, see below.</para>
 539
 540           <para>Also see <ulink
 541           url="https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt</ulink> in the kernel
 542           documentation regarding <literal>accept_ra</literal>, but note that systemd's setting of
 543           <constant>1</constant> (i.e. true) corresponds to kernel's setting of <constant>2</constant>.</para>
 544         </listitem>
 545         </varlistentry>
 546         <varlistentry>
 547           <term><varname>IPv6DuplicateAddressDetection=</varname></term>
 548           <listitem><para>Configures the amount of IPv6 Duplicate
 549           Address Detection (DAD) probes to send. Defaults to unset.
 550         </para></listitem>
 551         </varlistentry>
 552         <varlistentry>
 553           <term><varname>IPv6HopLimit=</varname></term>
 554           <listitem><para>Configures IPv6 Hop Limit. For each router that
 555           forwards the packet, the hop limit is decremented by 1. When the
 556           hop limit field reaches zero, the packet is discarded.
 557           Defaults to unset.
 558         </para></listitem>
 559         </varlistentry>
 560         <varlistentry>
 561           <term><varname>ProxyARP=</varname></term>
 562           <listitem><para>A boolean. Configures proxy ARP. Proxy ARP is the technique in which one host,
 563           usually a router, answers ARP requests intended for another machine. By "faking" its identity,
 564           the router accepts responsibility for routing packets to the "real" destination. (see <ulink
 565           url="https://tools.ietf.org/html/rfc1027">RFC 1027</ulink>.
 566           Defaults to unset.
 567         </para></listitem>
 568         </varlistentry>
 569         <varlistentry>
 570           <term><varname>Bridge=</varname></term>
 571           <listitem>
 572             <para>The name of the bridge to add the link to.</para>
 573           </listitem>
 574         </varlistentry>
 575         <varlistentry>
 576           <term><varname>Bond=</varname></term>
 577           <listitem>
 578             <para>The name of the bond to add the link to.</para>
 579           </listitem>
 580         </varlistentry>
 581         <varlistentry>
 582           <term><varname>VLAN=</varname></term>
 583           <listitem>
 584             <para>The name of a VLAN to create on the link. This
 585             option may be specified more than once.</para>
 586           </listitem>
 587         </varlistentry>
 588         <varlistentry>
 589           <term><varname>MACVLAN=</varname></term>
 590           <listitem>
 591             <para>The name of a MACVLAN to create on the link. This
 592             option may be specified more than once.</para>
 593           </listitem>
 594         </varlistentry>
 595         <varlistentry>
 596           <term><varname>VXLAN=</varname></term>
 597           <listitem>
 598             <para>The name of a VXLAN to create on the link. This
 599             option may be specified more than once.</para>
 600           </listitem>
 601         </varlistentry>
 602         <varlistentry>
 603           <term><varname>Tunnel=</varname></term>
 604           <listitem>
 605             <para>The name of a Tunnel to create on the link. This
 606             option may be specified more than once.</para>
 607           </listitem>
 608         </varlistentry>
 609       </variablelist>
 610
 611   </refsect1>
 612
 613   <refsect1>
 614     <title>[Address] Section Options</title>
 615
 616       <para>An <literal>[Address]</literal> section accepts the
 617       following keys. Specify several <literal>[Address]</literal>
 618       sections to configure several addresses.</para>
 619
 620       <variablelist class='network-directives'>
 621         <varlistentry>
 622           <term><varname>Address=</varname></term>
 623           <listitem>
 624             <para>As in the <literal>[Network]</literal> section. This
 625             key is mandatory.</para>
 626           </listitem>
 627         </varlistentry>
 628         <varlistentry>
 629           <term><varname>Peer=</varname></term>
 630           <listitem>
 631             <para>The peer address in a point-to-point connection.
 632             Accepts the same format as the <literal>Address</literal>
 633             key.</para>
 634           </listitem>
 635         </varlistentry>
 636         <varlistentry>
 637           <term><varname>Broadcast=</varname></term>
 638           <listitem>
 639             <para>The broadcast address, which must be in the format
 640             described in
 641             <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 642             This key only applies to IPv4 addresses. If it is not
 643             given, it is derived from the <literal>Address</literal>
 644             key.</para>
 645           </listitem>
 646         </varlistentry>
 647         <varlistentry>
 648           <term><varname>Label=</varname></term>
 649           <listitem>
 650             <para>An address label.</para>
 651           </listitem>
 652         </varlistentry>
 653         <varlistentry>
 654           <term><varname>PreferredLifetime=</varname></term>
 655           <listitem>
 656             <para>Allows the default "preferred lifetime" of the address to be overridden.
 657             Only three settings are accepted: <literal>forever</literal> or <literal>infinity</literal>
 658             which is the default and means that the address never expires, and <literal>0</literal> which means
 659             that the address is considered immediately "expired" and will not be used,
 660             unless explicitly requested. A setting of PreferredLifetime=0 is useful for
 661             addresses which are added to be used only by a specific application,
 662             which is then configured to use them explicitly.</para>
 663           </listitem>
 664         </varlistentry>
 665       </variablelist>
 666   </refsect1>
 667
 668   <refsect1>
 669     <title>[Route] Section Options</title>
 670       <para>The <literal>[Route]</literal> section accepts the
 671       following keys. Specify several <literal>[Route]</literal>
 672       sections to configure several routes.</para>
 673
 674       <variablelist class='network-directives'>
 675         <varlistentry>
 676           <term><varname>Gateway=</varname></term>
 677           <listitem>
 678             <para>As in the <literal>[Network]</literal> section.</para>
 679           </listitem>
 680         </varlistentry>
 681         <varlistentry>
 682           <term><varname>Destination=</varname></term>
 683           <listitem>
 684             <para>The destination prefix of the route. Possibly
 685             followed by a slash and the prefix length. If omitted, a
 686             full-length host route is assumed.</para>
 687           </listitem>
 688         </varlistentry>
 689         <varlistentry>
 690           <term><varname>Source=</varname></term>
 691           <listitem>
 692             <para>The source prefix of the route. Possibly followed by
 693             a slash and the prefix length. If omitted, a full-length
 694             host route is assumed.</para>
 695           </listitem>
 696         </varlistentry>
 697         <varlistentry>
 698           <term><varname>Metric=</varname></term>
 699           <listitem>
 700             <para>The metric of the route (an unsigned integer).</para>
 701           </listitem>
 702         </varlistentry>
 703         <varlistentry>
 704           <term><varname>Scope=</varname></term>
 705           <listitem>
 706             <para>The scope of the route, which can be <literal>global</literal>,
 707             <literal>link</literal> or <literal>host</literal>. Defaults to
 708             <literal>global</literal>.</para>
 709           </listitem>
 710         </varlistentry>
 711         <varlistentry>
 712           <term><varname>PreferredSource=</varname></term>
 713           <listitem>
 714             <para>The preferred source address of the route. The address
 715             must be in the format described in
 716             <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
 717           </listitem>
 718         </varlistentry>
 719         <varlistentry>
 720           <term><varname>Table=<replaceable>num</replaceable></varname></term>
 721           <listitem>
 722           <para>The table identifier for the route (a number between 1 and 4294967295, or 0 to unset).
 723           The table can be retrieved using <command>ip route show table <replaceable>num</replaceable></command>.
 724           </para>
 725           </listitem>
 726         </varlistentry>
 727       </variablelist>
 728   </refsect1>
 729
 730   <refsect1>
 731     <title>[DHCP] Section Options</title>
 732       <para>The <literal>[DHCP]</literal> section configures the
 733       DHCPv4 and DHCP6 client, if it is enabled with the
 734       <varname>DHCP=</varname> setting described above:</para>
 735
 736       <variablelist class='network-directives'>
 737         <varlistentry>
 738           <term><varname>UseDNS=</varname></term>
 739           <listitem>
 740             <para>When true (the default), the DNS servers received
 741             from the DHCP server will be used and take precedence over
 742             any statically configured ones.</para>
 743
 744             <para>This corresponds to the <option>nameserver</option>
 745             option in <citerefentry
 746             project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 747           </listitem>
 748         </varlistentry>
 749         <varlistentry>
 750           <term><varname>UseNTP=</varname></term>
 751           <listitem>
 752             <para>When true (the default), the NTP servers received
 753             from the DHCP server will be used by systemd-timesyncd
 754             and take precedence over any statically configured ones.</para>
 755           </listitem>
 756         </varlistentry>
 757         <varlistentry>
 758           <term><varname>UseMTU=</varname></term>
 759           <listitem>
 760             <para>When true, the interface maximum transmission unit
 761             from the DHCP server will be used on the current link.
 762             Defaults to false.</para>
 763           </listitem>
 764         </varlistentry>
 765         <varlistentry>
 766           <term><varname>SendHostname=</varname></term>
 767           <listitem>
 768             <para>When true (the default), the machine's hostname will
 769             be sent to the DHCP server.</para>
 770           </listitem>
 771         </varlistentry>
 772         <varlistentry>
 773           <term><varname>UseHostname=</varname></term>
 774           <listitem>
 775             <para>When true (the default), the hostname received from
 776             the DHCP server will be set as the transient hostname of the system
 777             </para>
 778           </listitem>
 779         </varlistentry>
 780         <varlistentry>
 781         <term><varname>Hostname=</varname></term>
 782         <listitem>
 783           <para>Use this value for the hostname which is sent to the
 784           DHCP server, instead of machine's hostname.</para>
 785         </listitem>
 786       </varlistentry>
 787         <varlistentry>
 788           <term><varname>UseDomains=</varname></term>
 789           <listitem>
 790             <para>Takes a boolean argument, or the special value <literal>route</literal>. When true, the domain name
 791             received from the DHCP server will be used as DNS search domain over this link, similar to the effect of
 792             the <option>Domains=</option> setting. If set to <literal>route</literal>, the domain name received from
 793             the DHCP server will be used for routing DNS queries only, but not for searching, similar to the effect of
 794             the <option>Domains=</option> setting when the argument is prefixed with <literal>~</literal>. Defaults to
 795             false.</para>
 796
 797             <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
 798             of all host names, in particular of single-label names. It is generally safer to use the supplied domain
 799             only as routing domain, rather than as search domain, in order to not have it affect local resolution of
 800             single-label names.</para>
 801
 802             <para>When set to true, this setting corresponds to the <option>domain</option> option in <citerefentry
 803             project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 804           </listitem>
 805         </varlistentry>
 806         <varlistentry>
 807           <term><varname>UseRoutes=</varname></term>
 808           <listitem>
 809             <para>When true (the default), the static routes will be
 810             requested from the DHCP server and added to the routing
 811             table with a metric of 1024.</para>
 812           </listitem>
 813         </varlistentry>
 814
 815         <varlistentry>
 816           <term><varname>UseTimezone=</varname></term>
 817
 818           <listitem><para>When true, the timezone received from the
 819           DHCP server will be set as timezone of the local
 820           system. Defaults to <literal>no</literal>.</para></listitem>
 821         </varlistentry>
 822
 823         <varlistentry>
 824           <term><varname>CriticalConnection=</varname></term>
 825           <listitem>
 826             <para>When true, the connection will never be torn down
 827             even if the DHCP lease expires. This is contrary to the
 828             DHCP specification, but may be the best choice if, say,
 829             the root filesystem relies on this connection. Defaults to
 830             false.</para>
 831           </listitem>
 832         </varlistentry>
 833
 834         <varlistentry>
 835           <term><varname>ClientIdentifier=</varname></term>
 836           <listitem>
 837             <para>The DHCPv4 client identifier to use. Either <literal>mac</literal> to use the MAC address of the link
 838             or <literal>duid</literal> (the default, see below) to use a RFC4361-compliant Client ID.</para>
 839           </listitem>
 840         </varlistentry>
 841
 842         <varlistentry>
 843           <term><varname>VendorClassIdentifier=</varname></term>
 844           <listitem>
 845             <para>The vendor class identifier used to identify vendor
 846             type and configuration.</para>
 847           </listitem>
 848         </varlistentry>
 849
 850         <varlistentry>
 851           <term><varname>DUIDType=</varname></term>
 852           <listitem>
 853             <para>Override the global <varname>DUIDType</varname> setting for this network. See
 854             <citerefentry><refentrytitle>networkd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 855             for a description of possible values.</para>
 856           </listitem>
 857         </varlistentry>
 858
 859         <varlistentry>
 860           <term><varname>DUIDRawData=</varname></term>
 861           <listitem>
 862             <para>Override the global <varname>DUIDRawData</varname> setting for this network. See
 863             <citerefentry><refentrytitle>networkd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 864             for a description of possible values.</para>
 865           </listitem>
 866         </varlistentry>
 867
 868         <varlistentry>
 869           <term><varname>IAID=</varname></term>
 870           <listitem>
 871             <para>The DHCP Identity Association Identifier (IAID) for the interface, a 32-bit unsigned integer.</para>
 872           </listitem>
 873         </varlistentry>
 874
 875         <varlistentry>
 876           <term><varname>RequestBroadcast=</varname></term>
 877           <listitem>
 878             <para>Request the server to use broadcast messages before
 879             the IP address has been configured. This is necessary for
 880             devices that cannot receive RAW packets, or that cannot
 881             receive packets at all before an IP address has been
 882             configured. On the other hand, this must not be enabled on
 883             networks where broadcasts are filtered out.</para>
 884           </listitem>
 885         </varlistentry>
 886
 887         <varlistentry>
 888           <term><varname>RouteMetric=</varname></term>
 889           <listitem>
 890             <para>Set the routing metric for routes specified by the
 891             DHCP server.</para>
 892           </listitem>
 893         </varlistentry>
 894       </variablelist>
 895     </refsect1>
 896
 897   <refsect1>
 898     <title>[IPv6AcceptRouterAdvertisements] Section Options</title>
 899       <para>The <literal>[IPv6AcceptRouterAdvertisements]</literal> section configures the IPv6 Router Advertisement
 900       (RA) client, if it is enabled with the <varname>IPv6AcceptRouterAdvertisements=</varname> setting described
 901       above:</para>
 902
 903       <variablelist class='network-directives'>
 904         <varlistentry>
 905           <term><varname>UseDNS=</varname></term>
 906           <listitem>
 907             <para>When true (the default), the DNS servers received in the Router Advertisement will be used and take
 908             precedence over any statically configured ones.</para>
 909
 910             <para>This corresponds to the <option>nameserver</option> option in <citerefentry
 911             project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 912           </listitem>
 913         </varlistentry>
 914
 915         <varlistentry>
 916           <term><varname>UseDomains=</varname></term>
 917           <listitem>
 918             <para>Takes a boolean argument, or the special value <literal>route</literal>. When true, the domain name
 919             received via IPv6 Router Advertisement (RA) will be used as DNS search domain over this link, similar to
 920             the effect of the <option>Domains=</option> setting. If set to <literal>route</literal>, the domain name
 921             received via IPv6 RA will be used for routing DNS queries only, but not for searching, similar to the
 922             effect of the <option>Domains=</option> setting when the argument is prefixed with
 923             <literal>~</literal>. Defaults to false.</para>
 924
 925             <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
 926             of all host names, in particular of single-label names. It is generally safer to use the supplied domain
 927             only as routing domain, rather than as search domain, in order to not have it affect local resolution of
 928             single-label names.</para>
 929
 930             <para>When set to true, this setting corresponds to the <option>domain</option> option in <citerefentry
 931             project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 932           </listitem>
 933         </varlistentry>
 934       </variablelist>
 935   </refsect1>
 936
 937
 938   <refsect1>
 939     <title>[DHCPServer] Section Options</title>
 940     <para>The <literal>[DHCPServer]</literal> section contains
 941     settings for the DHCP server, if enabled via the
 942     <varname>DHCPServer=</varname> option described above:</para>
 943
 944     <variablelist class='network-directives'>
 945
 946       <varlistentry>
 947         <term><varname>PoolOffset=</varname></term>
 948         <term><varname>PoolSize=</varname></term>
 949
 950         <listitem><para>Configures the pool of addresses to hand out. The pool
 951         is a contiguous sequence of IP addresses in the subnet configured for
 952         the server address, which does not include the subnet nor the broadcast
 953         address. <varname>PoolOffset=</varname> takes the offset of the pool
 954         from the start of subnet, or zero to use the default value.
 955         <varname>PoolSize=</varname> takes the number of IP addresses in the
 956         pool or zero to use the default value. By default, the pool starts at
 957         the first address after the subnet address and takes up the rest of
 958         the subnet, excluding the broadcast address. If the pool includes
 959         the server address (the default), this is reserved and not handed
 960         out to clients.</para></listitem>
 961       </varlistentry>
 962
 963       <varlistentry>
 964         <term><varname>DefaultLeaseTimeSec=</varname></term>
 965         <term><varname>MaxLeaseTimeSec=</varname></term>
 966
 967         <listitem><para>Control the default and maximum DHCP lease
 968         time to pass to clients. These settings take time values in seconds or
 969         another common time unit, depending on the suffix. The default
 970         lease time is used for clients that did not ask for a specific
 971         lease time. If a client asks for a lease time longer than the
 972         maximum lease time, it is automatically shortened to the
 973         specified time. The default lease time defaults to 1h, the
 974         maximum lease time to 12h. Shorter lease times are beneficial
 975         if the configuration data in DHCP leases changes frequently
 976         and clients shall learn the new settings with shorter
 977         latencies. Longer lease times reduce the generated DHCP
 978         network traffic.</para></listitem>
 979       </varlistentry>
 980
 981       <varlistentry>
 982         <term><varname>EmitDNS=</varname></term>
 983         <term><varname>DNS=</varname></term>
 984
 985         <listitem><para>Configures whether the DHCP leases handed out
 986         to clients shall contain DNS server information. The
 987         <varname>EmitDNS=</varname> setting takes a boolean argument
 988         and defaults to <literal>yes</literal>. The DNS servers to
 989         pass to clients may be configured with the
 990         <varname>DNS=</varname> option, which takes a list of IPv4
 991         addresses. If the <varname>EmitDNS=</varname> option is
 992         enabled but no servers configured, the servers are
 993         automatically propagated from an "uplink" interface that has
 994         appropriate servers set. The "uplink" interface is determined
 995         by the default route of the system with the highest
 996         priority. Note that this information is acquired at the time
 997         the lease is handed out, and does not take uplink interfaces
 998         into account that acquire DNS or NTP server information at a
 999         later point. DNS server propagation does not take
1000         <filename>/etc/resolv.conf</filename> into account. Also, note
1001         that the leases are not refreshed if the uplink network
1002         configuration changes. To ensure clients regularly acquire the
1003         most current uplink DNS server information, it is thus
1004         advisable to shorten the DHCP lease time via
1005         <varname>MaxLeaseTimeSec=</varname> described
1006         above.</para></listitem>
1007       </varlistentry>
1008
1009       <varlistentry>
1010         <term><varname>EmitNTP=</varname></term>
1011         <term><varname>NTP=</varname></term>
1012
1013         <listitem><para>Similar to the <varname>EmitDNS=</varname> and
1014         <varname>DNS=</varname> settings described above, these
1015         settings configure whether and what NTP server information
1016         shall be emitted as part of the DHCP lease. The same syntax,
1017         propagation semantics and defaults apply as for
1018         <varname>EmitDNS=</varname> and
1019         <varname>DNS=</varname>.</para></listitem>
1020       </varlistentry>
1021
1022       <varlistentry>
1023         <term><varname>EmitRouter=</varname></term>
1024
1025         <listitem><para>Similar to the <varname>EmitDNS=</varname>
1026         setting described above, this setting configures whether the
1027         DHCP lease should contain the router option. The same syntax,
1028         propagation semantics and defaults apply as for
1029         <varname>EmitDNS=</varname>.</para></listitem>
1030       </varlistentry>
1031
1032       <varlistentry>
1033         <term><varname>EmitTimezone=</varname></term>
1034         <term><varname>Timezone=</varname></term>
1035
1036         <listitem><para>Configures whether the DHCP leases handed out
1037         to clients shall contain timezone information. The
1038         <varname>EmitTimezone=</varname> setting takes a boolean
1039         argument and defaults to <literal>yes</literal>. The
1040         <varname>Timezone=</varname> setting takes a timezone string
1041         (such as <literal>Europe/Berlin</literal> or
1042         <literal>UTC</literal>) to pass to clients. If no explicit
1043         timezone is set, the system timezone of the local host is
1044         propagated, as determined by the
1045         <filename>/etc/localtime</filename> symlink.</para></listitem>
1046       </varlistentry>
1047
1048     </variablelist>
1049   </refsect1>
1050
1051   <refsect1>
1052     <title>[Bridge] Section Options</title>
1053       <para>The <literal>[Bridge]</literal> section accepts the
1054       following keys.</para>
1055       <variablelist class='network-directives'>
1056         <varlistentry>
1057           <term><varname>UnicastFlood=</varname></term>
1058           <listitem>
1059             <para>A boolean. Controls whether the bridge should flood
1060             traffic for which an FDB entry is missing and the destination
1061             is unknown through this port. Defaults to on.
1062             </para>
1063           </listitem>
1064         </varlistentry>
1065         <varlistentry>
1066           <term><varname>HairPin=</varname></term>
1067           <listitem>
1068             <para>A boolean. Configures whether traffic may be sent back
1069             out of the port on which it was received. By default, this
1070             flag is false, and the bridge will not forward traffic back
1071             out of the receiving port.</para>
1072           </listitem>
1073         </varlistentry>
1074         <varlistentry>
1075           <term><varname>UseBPDU=</varname></term>
1076           <listitem>
1077             <para>A boolean. Configures whether STP Bridge Protocol Data Units will be
1078             processed by the bridge port. Defaults to yes.</para>
1079           </listitem>
1080         </varlistentry>
1081         <varlistentry>
1082           <term><varname>FastLeave=</varname></term>
1083           <listitem>
1084             <para>A boolean. This flag allows the bridge to immediately stop multicast
1085             traffic on a port that receives an IGMP Leave message. It is only used with
1086             IGMP snooping if enabled on the bridge. Defaults to off.</para>
1087           </listitem>
1088         </varlistentry>
1089         <varlistentry>
1090           <term><varname>AllowPortToBeRoot=</varname></term>
1091           <listitem>
1092             <para>A boolean. Configures whether a given port is allowed to
1093             become a root port. Only used when STP is enabled on the bridge.
1094             Defaults to on.</para>
1095           </listitem>
1096         </varlistentry>
1097         <varlistentry>
1098           <term><varname>Cost=</varname></term>
1099           <listitem>
1100             <para>Sets the "cost" of sending packets of this interface.
1101             Each port in a bridge may have a different speed and the cost
1102             is used to decide which link to use. Faster interfaces
1103             should have lower costs.</para>
1104           </listitem>
1105         </varlistentry>
1106       </variablelist>
1107   </refsect1>
1108   <refsect1>
1109     <title>[BridgeFDB] Section Options</title>
1110       <para>The <literal>[BridgeFDB]</literal> section manages the
1111       forwarding database table of a port and accepts the following
1112       keys. Specify several <literal>[BridgeFDB]</literal> sections to
1113       configure several static MAC table entries.</para>
1114
1115       <variablelist class='network-directives'>
1116         <varlistentry>
1117           <term><varname>MACAddress=</varname></term>
1118           <listitem>
1119             <para>As in the <literal>[Network]</literal> section. This
1120             key is mandatory.</para>
1121           </listitem>
1122         </varlistentry>
1123         <varlistentry>
1124           <term><varname>VLANId=</varname></term>
1125           <listitem>
1126             <para>The VLAN ID for the new static MAC table entry. If
1127             omitted, no VLAN ID info is appended to the new static MAC
1128             table entry.</para>
1129           </listitem>
1130         </varlistentry>
1131       </variablelist>
1132   </refsect1>
1133
1134   <refsect1>
1135     <title>Example</title>
1136     <example>
1137       <title>/etc/systemd/network/50-static.network</title>
1138
1139       <programlisting>[Match]
1140 Name=enp2s0
1141
1142 [Network]
1143 Address=192.168.0.15/24
1144 Gateway=192.168.0.1</programlisting>
1145     </example>
1146
1147     <example>
1148       <title>/etc/systemd/network/80-dhcp.network</title>
1149
1150       <programlisting>[Match]
1151 Name=en*
1152
1153 [Network]
1154 DHCP=yes</programlisting>
1155     </example>
1156
1157     <example>
1158       <title>/etc/systemd/network/25-bridge-static.network</title>
1159
1160       <programlisting>[Match]
1161 Name=bridge0
1162
1163 [Network]
1164 Address=192.168.0.15/24
1165 Gateway=192.168.0.1
1166 DNS=192.168.0.1</programlisting>
1167     </example>
1168
1169     <example>
1170       <title>/etc/systemd/network/25-bridge-slave-interface.network</title>
1171
1172       <programlisting>[Match]
1173 Name=enp2s0
1174
1175 [Network]
1176 Bridge=bridge0</programlisting>
1177     </example>
1178     <example>
1179       <title>/etc/systemd/network/25-ipip.network</title>
1180
1181       <programlisting>[Match]
1182 Name=em1
1183
1184 [Network]
1185 Tunnel=ipip-tun</programlisting>
1186     </example>
1187
1188     <example>
1189       <title>/etc/systemd/network/25-sit.network</title>
1190
1191       <programlisting>[Match]
1192 Name=em1
1193
1194 [Network]
1195 Tunnel=sit-tun</programlisting>
1196     </example>
1197
1198     <example>
1199       <title>/etc/systemd/network/25-gre.network</title>
1200
1201       <programlisting>[Match]
1202 Name=em1
1203
1204 [Network]
1205 Tunnel=gre-tun</programlisting>
1206     </example>
1207
1208     <example>
1209       <title>/etc/systemd/network/25-vti.network</title>
1210
1211       <programlisting>[Match]
1212 Name=em1
1213
1214 [Network]
1215 Tunnel=vti-tun</programlisting>
1216     </example>
1217
1218     <example>
1219       <title>/etc/systemd/network/25-bond.network</title>
1220
1221       <programlisting>[Match]
1222 Name=bond1
1223
1224 [Network]
1225 DHCP=yes
1226 </programlisting>
1227     </example>
1228
1229   </refsect1>
1230
1231   <refsect1>
1232     <title>See Also</title>
1233     <para>
1234       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1235       <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1236       <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1237       <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1238       <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
1239     </para>
1240   </refsect1>
1241
1242 </refentry>