summaryrefslogtreecommitdiff
path: root/man/systemd.netdev.xml
blob: 3cc58ca854d566537deadceea0c7732bb6f024fd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

<!--
  This file is part of systemd.

  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.netdev" 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.netdev</refentrytitle>
    <manvolnum>5</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>systemd.netdev</refname>
    <refpurpose>Virtual Network Device configuration</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <para><filename><replaceable>netdev</replaceable>.netdev</filename></para>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para>Network setup is performed by
    <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
    </para>

    <para>Virtual Network Device files must have the extension
    <filename>.netdev</filename>; other extensions are ignored.
    Virtual network devices are created as soon as networkd is
    started. If a netdev with the specified name already exists,
    networkd will use that as-is rather than create its own. Note that
    the settings of the pre-existing netdev will not be changed by
    networkd.</para>

    <para>The <filename>.netdev</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>
  </refsect1>

  <refsect1>
    <title>Supported netdev kinds</title>

    <para>The following kinds of virtual network devices may be
    configured in <filename>.netdev</filename> files:</para>

    <table>
      <title>Supported kinds of virtual network devices</title>

      <tgroup cols='2'>
        <colspec colname='kind' />
        <colspec colname='explanation' />
        <thead><row>
          <entry>Kind</entry>
          <entry>Description</entry>
        </row></thead>
        <tbody>
          <row><entry><varname>bond</varname></entry>
          <entry>A bond device is an aggregation of all its slave devices. See <ulink url="https://www.kernel.org/doc/Documentation/networking/bonding.txt">Linux Ethernet Bonding Driver HOWTO</ulink> for details.Local configuration</entry></row>

          <row><entry><varname>bridge</varname></entry>
          <entry>A bridge device is a software switch, and each of its slave devices and the bridge itself are ports of the switch.</entry></row>

          <row><entry><varname>dummy</varname></entry>
          <entry>A dummy device drops all packets sent to it.</entry></row>

          <row><entry><varname>gre</varname></entry>
          <entry>A Level 3 GRE tunnel over IPv4. See <ulink url="https://tools.ietf.org/html/rfc2784">RFC 2784</ulink> for details.</entry></row>

          <row><entry><varname>gretap</varname></entry>
          <entry>A Level 2 GRE tunnel over IPv4.</entry></row>

          <row><entry><varname>ip6gre</varname></entry>
          <entry>A Level 3 GRE tunnel over IPv6.</entry></row>

          <row><entry><varname>ip6tnl</varname></entry>
          <entry>An IPv4 or IPv6 tunnel over IPv6</entry></row>

          <row><entry><varname>ip6gretap</varname></entry>
          <entry>An Level 2 GRE tunnel over IPv6.</entry></row>

          <row><entry><varname>ipip</varname></entry>
          <entry>An IPv4 over IPv4 tunnel.</entry></row>

          <row><entry><varname>ipvlan</varname></entry>
          <entry>An ipvlan device is a stacked device which receives packets from its underlying device based on IP address filtering.</entry></row>

          <row><entry><varname>macvlan</varname></entry>
          <entry>A macvlan device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>

          <row><entry><varname>macvtap</varname></entry>
          <entry>A macvtap device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>

          <row><entry><varname>sit</varname></entry>
          <entry>An IPv6 over IPv4 tunnel.</entry></row>

          <row><entry><varname>tap</varname></entry>
          <entry>A persistent Level 2 tunnel between a network device and a device node.</entry></row>

          <row><entry><varname>tun</varname></entry>
          <entry>A persistent Level 3 tunnel between a network device and a device node.</entry></row>

          <row><entry><varname>veth</varname></entry>
          <entry>An Ethernet tunnel between a pair of network devices.</entry></row>

          <row><entry><varname>vlan</varname></entry>
          <entry>A VLAN is a stacked device which receives packets from its underlying device based on VLAN tagging. See <ulink url="http://www.ieee802.org/1/pages/802.1Q.html">IEEE 802.1Q</ulink> for details.</entry></row>

          <row><entry><varname>vti</varname></entry>
          <entry>An IPv4 over IPSec tunnel.</entry></row>

          <row><entry><varname>vti6</varname></entry>
          <entry>An IPv6 over IPSec tunnel.</entry></row>

          <row><entry><varname>vxlan</varname></entry>
          <entry>A virtual extensible LAN (vxlan), for connecting Cloud computing deployments.</entry></row>
        </tbody>
      </tgroup>
    </table>

  </refsect1>

  <refsect1>
    <title>[Match] Section Options</title>

    <para>A virtual network device is only created if the
    <literal>[Match]</literal> section matches the current
    environment, or if the section is empty. The following keys are
    accepted:</para>

    <variablelist class='network-directives'>
      <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>[NetDev] Section Options</title>

      <para>The <literal>[NetDev]</literal> section accepts the
      following keys:</para>

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>Description=</varname></term>
          <listitem>
            <para>A free-form description of the netdev.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Name=</varname></term>
          <listitem>
            <para>The interface name used when creating the netdev.
            This option is compulsory.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Kind=</varname></term>
          <listitem>
            <para>The netdev kind. This option is compulsory. See the
            <literal>Supported netdev kinds</literal> section for the
            valid keys.</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. This key is not
            currently supported for <literal>tun</literal> or
            <literal>tap</literal> devices.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>MACAddress=</varname></term>
          <listitem>
            <para>The MAC address to use for the device. If none is
            given, one is generated based on the interface name and
            the
            <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
            This key is not currently supported for
            <literal>tun</literal> or <literal>tap</literal> devices.
            </para>
          </listitem>
        </varlistentry>
      </variablelist>
  </refsect1>

    <refsect1>
    <title>[Bridge] Section Options</title>

      <para>The <literal>[Bridge]</literal> section only applies for
      netdevs of kind <literal>bridge</literal>, and accepts the
      following keys:</para>

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>HelloTimeSec=</varname></term>
          <listitem>
            <para>HelloTimeSec specifies the number of seconds between two hello packets
            sent out by the root bridge and the designated bridges. Hello packets are
            used to communicate information about the topology throughout the entire
            bridged local area network.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>MaxAgeSec=</varname></term>
          <listitem>
            <para>MaxAgeSec specifies the number of seconds of maximum message age.
            If the last seen (received) hello packet is more than this number of
            seconds old, the bridge in question will start the takeover procedure
            in attempt to become the Root Bridge itself.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>ForwardDelaySec=</varname></term>
          <listitem>
            <para>ForwardDelaySec specifies the number of seconds spent in each
            of the Listening and Learning states before the Forwarding state is entered.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>MulticastQuerier=</varname></term>
          <listitem>
            <para>A boolean. This setting controls the IFLA_BR_MCAST_QUERIER option in the kernel.
            If enabled, the kernel will send general ICMP queries from a zero source address.
            This feature should allow faster convergence on startup, but it causes some
            multicast-aware switches to misbehave and disrupt forwarding of multicast packets.
            When unset, the kernel's default setting applies.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>MulticastSnooping=</varname></term>
          <listitem>
            <para>A boolean. This setting controls the IFLA_BR_MCAST_SNOOPING option in the kernel.
            If enabled, IGMP snooping monitors the Internet Group Management Protocol (IGMP) traffic
            between hosts and multicast routers. When unset, the kernel's default setting applies.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>VLANFiltering=</varname></term>
          <listitem>
            <para>A boolean. This setting controls the IFLA_BR_VLAN_FILTERING option in the kernel.
            If enabled, the bridge will be started in VLAN-filtering mode. When unset, the kernel's
            default setting applies.
            </para>
          </listitem>
        </varlistentry>
      </variablelist>

  </refsect1>

  <refsect1>
    <title>[VLAN] Section Options</title>

      <para>The <literal>[VLAN]</literal> section only applies for
      netdevs of kind <literal>vlan</literal>, and accepts the
      following key:</para>

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>Id=</varname></term>
          <listitem>
            <para>The VLAN ID to use. An integer in the range 0–4094.
            This option is compulsory.</para>
          </listitem>
        </varlistentry>
      </variablelist>

  </refsect1>

  <refsect1>
    <title>[MACVLAN] Section Options</title>

    <para>The <literal>[MACVLAN]</literal> section only applies for
    netdevs of kind <literal>macvlan</literal>, and accepts the
    following key:</para>

    <variablelist class='network-directives'>
      <varlistentry>
        <term><varname>Mode=</varname></term>
        <listitem>
          <para>The MACVLAN mode to use. The supported options are
          <literal>private</literal>,
          <literal>vepa</literal>,
          <literal>bridge</literal>, and
          <literal>passthru</literal>.
          </para>
        </listitem>
      </varlistentry>
    </variablelist>

  </refsect1>

    <refsect1>
    <title>[MACVTAP] Section Options</title>

    <para>The <literal>[MACVTAP]</literal> section applies for
    netdevs of kind <literal>macvtap</literal> and accepts the
    same key as <literal>[MACVLAN]</literal>.</para>

    </refsect1>

  <refsect1>
    <title>[IPVLAN] Section Options</title>

    <para>The <literal>[IPVLAN]</literal> section only applies for
    netdevs of kind <literal>ipvlan</literal>, and accepts the
    following key:</para>

    <variablelist class='network-directives'>
      <varlistentry>
        <term><varname>Mode=</varname></term>
          <listitem>
            <para>The IPVLAN mode to use. The supported options are
            <literal>L2</literal> and <literal>L3</literal>.
            </para>
          </listitem>
      </varlistentry>
    </variablelist>

  </refsect1>

  <refsect1>
    <title>[VXLAN] Section Options</title>
    <para>The <literal>[VXLAN]</literal> section only applies for
    netdevs of kind <literal>vxlan</literal>, and accepts the
    following keys:</para>

    <variablelist class='network-directives'>
      <varlistentry>
        <term><varname>Id=</varname></term>
        <listitem>
          <para>The VXLAN ID to use.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Group=</varname></term>
        <listitem>
          <para>An assigned multicast group IP address.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>TOS=</varname></term>
        <listitem>
          <para>The Type Of Service byte value for a vxlan interface.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>TTL=</varname></term>
        <listitem>
          <para>A fixed Time To Live N on Virtual eXtensible Local
          Area Network packets. N is a number in the range 1–255. 0
          is a special value meaning that packets inherit the TTL
          value.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>MacLearning=</varname></term>
        <listitem>
          <para>A boolean. When true, enables dynamic MAC learning
          to discover remote MAC addresses.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>FDBAgeingSec=</varname></term>
        <listitem>
          <para>The lifetime of Forwarding Database entry learnt by
          the kernel, in seconds.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>MaximumFDBEntries=</varname></term>
        <listitem>
          <para>Configures maximum number of FDB entries.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>ARPProxy=</varname></term>
        <listitem>
          <para>A boolean. When true, enables ARP proxying.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>L2MissNotification=</varname></term>
        <listitem>
          <para>A boolean. When true, enables netlink LLADDR miss
          notifications.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>L3MissNotification=</varname></term>
        <listitem>
          <para>A boolean. When true, enables netlink IP address miss
          notifications.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>RouteShortCircuit=</varname></term>
        <listitem>
          <para>A boolean. When true, route short circuiting is turned
          on.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>UDPCheckSum=</varname></term>
        <listitem>
          <para>A boolean. When true, transmitting UDP checksums when doing VXLAN/IPv4 is turned on.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>UDP6ZeroChecksumTx=</varname></term>
        <listitem>
          <para>A boolean. When true, sending zero checksums in VXLAN/IPv6 is turned on.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>UDP6ZeroCheckSumRx=</varname></term>
        <listitem>
          <para>A boolean. When true, receiving zero checksums in VXLAN/IPv6 is turned on.</para>
        </listitem>
      </varlistentry>
    <varlistentry>
      <term><varname>GroupPolicyExtension=</varname></term>
      <listitem>
        <para>A boolean. When true, it enables Group Policy VXLAN extension security label mechanism
        across network peers based on VXLAN. For details about the Group Policy VXLAN, see the
        <ulink url="https://tools.ietf.org/html/draft-smith-vxlan-group-policy">
        VXLAN Group Policy </ulink> document. Defaults to false.</para>
      </listitem>
    </varlistentry>
    <varlistentry>
      <term><varname>DestinationPort=</varname></term>
      <listitem>
        <para>Configures the default destination UDP port on a per-device basis.
        If destination port is not specified then Linux kernel default will be used.
        Set destination port 4789 to get the IANA assigned value,
        and destination port 0 to get default values.</para>
      </listitem>
    </varlistentry>
    <varlistentry>
      <term><varname>PortRange=</varname></term>
        <listitem>
          <para>Configures VXLAN port range. VXLAN bases source
          UDP port based on flow to help the receiver to be able
          to load balance based on outer header flow. It
          restricts the port range to the normal UDP local
          ports, and allows overriding via configuration.</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>
  <refsect1>
    <title>[Tunnel] Section Options</title>

    <para>The <literal>[Tunnel]</literal> section only applies for
    netdevs of kind
    <literal>ipip</literal>,
    <literal>sit</literal>,
    <literal>gre</literal>,
    <literal>gretap</literal>,
    <literal>ip6gre</literal>,
    <literal>ip6gretap</literal>,
    <literal>vti</literal>,
    <literal>vti6</literal>, and
    <literal>ip6tnl</literal> and accepts
    the following keys:</para>

    <variablelist class='network-directives'>
      <varlistentry>
        <term><varname>Local=</varname></term>
        <listitem>
          <para>A static local address for tunneled packets. It must
          be an address on another interface of this host.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Remote=</varname></term>
        <listitem>
          <para>The remote endpoint of the tunnel.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>TOS=</varname></term>
        <listitem>
          <para>The Type Of Service byte value for a tunnel interface.
          For details about the TOS, see the
          <ulink url="http://tools.ietf.org/html/rfc1349"> Type of
          Service in the Internet Protocol Suite </ulink> document.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>TTL=</varname></term>
        <listitem>
          <para>A fixed Time To Live N on tunneled packets. N is a
          number in the range 1–255. 0 is a special value meaning that
          packets inherit the TTL value. The default value for IPv4
          tunnels is: inherit. The default value for IPv6 tunnels is
          64.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>DiscoverPathMTU=</varname></term>
        <listitem>
          <para>A boolean. When true, enables Path MTU Discovery on
          the tunnel.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>IPv6FlowLabel=</varname></term>
        <listitem>
          <para>Configures the 20-bit flow label (see <ulink url="https://tools.ietf.org/html/rfc6437">
          RFC 6437</ulink>) field in the IPv6 header (see <ulink url="https://tools.ietf.org/html/rfc2460">
          RFC 2460</ulink>), which is used by a node to label packets of a flow.
          It is only used for IPv6 tunnels.
          A flow label of zero is used to indicate packets that have
          not been labeled.
          It can be configured to a value in the range 0–0xFFFFF, or be
          set to <literal>inherit</literal>, in which case the original flowlabel is used.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>CopyDSCP=</varname></term>
        <listitem>
          <para>A boolean. When true, the Differentiated Service Code
          Point (DSCP) field will be copied to the inner header from
          outer header during the decapsulation of an IPv6 tunnel
          packet. DSCP is a field in an IP packet that enables different
          levels of service to be assigned to network traffic.
          Defaults to <literal>no</literal>.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>EncapsulationLimit=</varname></term>
        <listitem>
          <para>The Tunnel Encapsulation Limit option specifies how many additional
          levels of encapsulation are permitted to be prepended to the packet.
          For example, a Tunnel Encapsulation Limit option containing a limit
          value of zero means that a packet carrying that option may not enter
          another tunnel before exiting the current tunnel.
          (see <ulink url="https://tools.ietf.org/html/rfc2473#section-4.1.1"> RFC 2473</ulink>).
          The valid range is 0–255 and <literal>none</literal>. Defaults to 4.
        </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Key=</varname></term>
        <listitem>
          <para>The <varname>Key=</varname> parameter specifies the same key to use in
          both directions (<varname>InputKey=</varname> and <varname>OutputKey=</varname>).
          The <varname>Key=</varname> is either a number or an IPv4 address-like dotted quad.
          It is used as mark-configured SAD/SPD entry as part of the lookup key (both in data
          and control path) in ip xfrm (framework used to implement IPsec protocol).
          See <ulink url="http://man7.org/linux/man-pages/man8/ip-xfrm.8.html">
          ip-xfrm - transform configuration</ulink> for details. It is only used for VTI/VTI6
          tunnels.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>InputKey=</varname></term>
        <listitem>
          <para>The <varname>InputKey=</varname> parameter specifies the key to use for input.
          The format is same as <varname>Key=</varname>. It is only used for VTI/VTI6 tunnels.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>OutputKey=</varname></term>
        <listitem>
          <para>The <varname>OutputKey=</varname> parameter specifies the key to use for output.
          The format is same as <varname>Key=</varname>. It is only used for VTI/VTI6 tunnels.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Mode=</varname></term>
        <listitem>
          <para>An <literal>ip6tnl</literal> tunnel can be in one of three
          modes
          <literal>ip6ip6</literal> for IPv6 over IPv6,
          <literal>ipip6</literal> for IPv4 over IPv6 or
          <literal>any</literal> for either.
          </para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>
  <refsect1>
    <title>[Peer] Section Options</title>

      <para>The <literal>[Peer]</literal> section only applies for
      netdevs of kind <literal>veth</literal> and accepts the
      following keys:</para>

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>Name=</varname></term>
          <listitem>
            <para>The interface name used when creating the netdev.
            This option is compulsory.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>MACAddress=</varname></term>
          <listitem>
            <para>The peer MACAddress, if not set, it is generated in
            the same way as the MAC address of the main
            interface.</para>
          </listitem>
        </varlistentry>
      </variablelist>
  </refsect1>
  <refsect1>
    <title>[Tun] Section Options</title>

    <para>The <literal>[Tun]</literal> section only applies for
    netdevs of kind <literal>tun</literal>, and accepts the following
    keys:</para>

    <variablelist class='network-directives'>
      <varlistentry>
        <term><varname>OneQueue=</varname></term>
        <listitem><para>Takes a boolean argument. Configures whether
        all packets are queued at the device (enabled), or a fixed
        number of packets are queued at the device and the rest at the
        <literal>qdisc</literal>. Defaults to
        <literal>no</literal>.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>MultiQueue=</varname></term>
        <listitem><para>Takes a boolean argument. Configures whether
        to use multiple file descriptors (queues) to parallelize
        packets sending and receiving. Defaults to
        <literal>no</literal>.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>PacketInfo=</varname></term>
        <listitem><para>Takes a boolean argument. Configures whether
        packets should be prepended with four extra bytes (two flag
        bytes and two protocol bytes). If disabled, it indicates that
        the packets will be pure IP packets. Defaults to
        <literal>no</literal>.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>VNetHeader=</varname></term>
        <listitem><para>Takes a boolean argument. Configures
        IFF_VNET_HDR flag for a tap device. It allows sending
        and receiving larger Generic Segmentation Offload (GSO)
        packets. This may increase throughput significantly.
        Defaults to
        <literal>no</literal>.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>User=</varname></term>
        <listitem><para>User to grant access to the
        <filename>/dev/net/tun</filename> device.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Group=</varname></term>
        <listitem><para>Group to grant access to the
        <filename>/dev/net/tun</filename> device.</para>
        </listitem>
      </varlistentry>

    </variablelist>

  </refsect1>

  <refsect1>
    <title>[Tap] Section Options</title>

    <para>The <literal>[Tap]</literal> section only applies for
    netdevs of kind <literal>tap</literal>, and accepts the same keys
    as the <literal>[Tun]</literal> section.</para>
  </refsect1>

  <refsect1>
    <title>[Bond] Section Options</title>

    <para>The <literal>[Bond]</literal> section accepts the following
    key:</para>

    <variablelist class='network-directives'>
      <varlistentry>
        <term><varname>Mode=</varname></term>
        <listitem>
          <para>Specifies one of the bonding policies. The default is
          <literal>balance-rr</literal> (round robin). Possible values are
          <literal>balance-rr</literal>,
          <literal>active-backup</literal>,
          <literal>balance-xor</literal>,
          <literal>broadcast</literal>,
          <literal>802.3ad</literal>,
          <literal>balance-tlb</literal>, and
          <literal>balance-alb</literal>.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>TransmitHashPolicy=</varname></term>
        <listitem>
          <para>Selects the transmit hash policy to use for slave
          selection in balance-xor, 802.3ad, and tlb modes. Possible
          values are
          <literal>layer2</literal>,
          <literal>layer3+4</literal>,
          <literal>layer2+3</literal>,
          <literal>encap2+3</literal>,
          <literal>802.3ad</literal>, and
          <literal>encap3+4</literal>.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>LACPTransmitRate=</varname></term>
        <listitem>
          <para>Specifies the rate with which link partner transmits
          Link Aggregation Control Protocol Data Unit packets in
          802.3ad mode. Possible values are <literal>slow</literal>,
          which requests partner to transmit LACPDUs every 30 seconds,
          and <literal>fast</literal>, which requests partner to
          transmit LACPDUs every second. The default value is
          <literal>slow</literal>.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>MIIMonitorSec=</varname></term>
        <listitem>
          <para>Specifies the frequency that Media Independent
          Interface link monitoring will occur. A value of zero
          disables MII link monitoring. This value is rounded down to
          the nearest millisecond. The default value is 0.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>UpDelaySec=</varname></term>
        <listitem>
          <para>Specifies the delay before a link is enabled after a
          link up status has been detected. This value is rounded down
          to a multiple of MIIMonitorSec. The default value is
          0.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>DownDelaySec=</varname></term>
        <listitem>
          <para>Specifies the delay before a link is disabled after a
          link down status has been detected. This value is rounded
          down to a multiple of MIIMonitorSec. The default value is
          0.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>LearnPacketIntervalSec=</varname></term>
        <listitem>
          <para>Specifies the number of seconds between instances where the bonding
          driver sends learning packets to each slave peer switch.
          The valid range is 1–0x7fffffff; the default value is 1. This option
          has an effect only for the balance-tlb and balance-alb modes.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>AdSelect=</varname></term>
        <listitem>
          <para>Specifies the 802.3ad aggregation selection logic to use. Possible values are
          <literal>stable</literal>,
          <literal>bandwidth</literal> and
          <literal>count</literal>.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>FailOverMACPolicy=</varname></term>
        <listitem>
          <para>Specifies whether the active-backup mode should set all slaves to
          the same MAC address at the time of enslavement or, when enabled, to perform special handling of the
          bond's MAC address in accordance with the selected policy. The default policy is none.
          Possible values are
          <literal>none</literal>,
          <literal>active</literal> and
          <literal>follow</literal>.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>ARPValidate=</varname></term>
        <listitem>
          <para>Specifies whether or not ARP probes and replies should be
          validated in any mode that supports ARP monitoring, or whether
          non-ARP traffic should be filtered (disregarded) for link
          monitoring purposes. Possible values are
          <literal>none</literal>,
          <literal>active</literal>,
          <literal>backup</literal> and
          <literal>all</literal>.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>ARPIntervalSec=</varname></term>
        <listitem>
          <para>Specifies the ARP link monitoring frequency in milliseconds.
          A value of 0 disables ARP monitoring. The default value is 0.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>ARPIPTargets=</varname></term>
        <listitem>
          <para>Specifies the IP addresses to use as ARP monitoring peers when
          ARPIntervalSec is greater than 0. These are the targets of the ARP request
          sent to determine the health of the link to the targets.
          Specify these values in IPv4 dotted decimal format. At least one IP
          address must be given for ARP monitoring to function. The
          maximum number of targets that can be specified is 16. The
          default value is no IP addresses.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>ARPAllTargets=</varname></term>
        <listitem>
          <para>Specifies the quantity of ARPIPTargets that must be reachable
          in order for the ARP monitor to consider a slave as being up.
          This option affects only active-backup mode for slaves with
          ARPValidate enabled. Possible values are
          <literal>any</literal> and
          <literal>all</literal>.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>PrimaryReselectPolicy=</varname></term>
        <listitem>
          <para>Specifies the reselection policy for the primary slave.  This
          affects how the primary slave is chosen to become the active slave
          when failure of the active slave or recovery of the primary slave
          occurs. This option is designed to prevent flip-flopping between
          the primary slave and other slaves.  Possible values are
          <literal>always</literal>,
          <literal>better</literal> and
          <literal>failure</literal>.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>ResendIGMP=</varname></term>
        <listitem>
          <para>Specifies the number of IGMP membership reports to be issued after
          a failover event. One membership report is issued immediately after
          the failover, subsequent packets are sent in each 200ms interval.
          The valid range is 0–255. Defaults to 1. A value of 0
          prevents the IGMP membership report from being issued in response
          to the failover event.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>PacketsPerSlave=</varname></term>
        <listitem>
          <para>Specify the number of packets to transmit through a slave before
            moving to the next one. When set to 0, then a slave is chosen at
            random. The valid range is 0–65535. Defaults to 1. This option
            only has effect when in balance-rr mode.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>GratuitousARP=</varname></term>
        <listitem>
          <para>Specify the number of peer notifications (gratuitous ARPs and
            unsolicited IPv6 Neighbor Advertisements) to be issued after a
            failover event.  As soon as the link is up on the new slave,
            a peer notification is sent on the  bonding device and each
            VLAN sub-device.  This is repeated at each link monitor interval
            (ARPIntervalSec or MIIMonitorSec, whichever is active) if the number is
            greater than 1. The valid range is 0–255. The default value is 1.
            These options affect only the active-backup mode.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>AllSlavesActive=</varname></term>
        <listitem>
          <para>A boolean. Specifies that duplicate frames (received on inactive ports)
          should be dropped when false, or delivered when true. Normally, bonding will drop
          duplicate frames (received on inactive ports), which is desirable for
          most users. But there are some times it is nice to allow duplicate
          frames to be delivered. The default value is false (drop duplicate frames
          received on inactive ports).
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>MinLinks=</varname></term>
        <listitem>
          <para>Specifies the minimum number of links that must be active before
          asserting carrier. The default value is 0.
          </para>
        </listitem>
      </varlistentry>

    </variablelist>

    <para>For more detail information see
    <ulink url="https://www.kernel.org/doc/Documentation/networking/bonding.txt">
    Linux Ethernet Bonding Driver HOWTO</ulink></para>

  </refsect1>

  <refsect1>
    <title>Example</title>
    <example>
      <title>/etc/systemd/network/25-bridge.netdev</title>

      <programlisting>[NetDev]
Name=bridge0
Kind=bridge</programlisting>
    </example>

    <example>
      <title>/etc/systemd/network/25-vlan1.netdev</title>

      <programlisting>[Match]
Virtualization=no

[NetDev]
Name=vlan1
Kind=vlan

[VLAN]
Id=1</programlisting>
    </example>
    <example>
      <title>/etc/systemd/network/25-ipip.netdev</title>
      <programlisting>[NetDev]
Name=ipip-tun
Kind=ipip
MTUBytes=1480

[Tunnel]
Local=192.168.223.238
Remote=192.169.224.239
TTL=64</programlisting>
    </example>
    <example>
      <title>/etc/systemd/network/25-tap.netdev</title>
      <programlisting>[NetDev]
Name=tap-test
Kind=tap

[Tap]
MultiQueue=true
PacketInfo=true</programlisting> </example>

    <example>
      <title>/etc/systemd/network/25-sit.netdev</title>
      <programlisting>[NetDev]
Name=sit-tun
Kind=sit
MTUBytes=1480

[Tunnel]
Local=10.65.223.238
Remote=10.65.223.239</programlisting>
    </example>

    <example>
      <title>/etc/systemd/network/25-gre.netdev</title>
      <programlisting>[NetDev]
Name=gre-tun
Kind=gre
MTUBytes=1480

[Tunnel]
Local=10.65.223.238
Remote=10.65.223.239</programlisting>
    </example>

    <example>
      <title>/etc/systemd/network/25-vti.netdev</title>

      <programlisting>[NetDev]
Name=vti-tun
Kind=vti
MTUBytes=1480

[Tunnel]
Local=10.65.223.238
Remote=10.65.223.239</programlisting>
    </example>

    <example>
      <title>/etc/systemd/network/25-veth.netdev</title>
      <programlisting>[NetDev]
Name=veth-test
Kind=veth

[Peer]
Name=veth-peer</programlisting>
    </example>

    <example>
      <title>/etc/systemd/network/25-bond.netdev</title>
      <programlisting>[NetDev]
Name=bond1
Kind=bond

[Bond]
Mode=802.3ad
TransmitHashPolicy=layer3+4
MIIMonitorSec=1s
LACPTransmitRate=fast
</programlisting>
    </example>

    <example>
      <title>/etc/systemd/network/25-dummy.netdev</title>
      <programlisting>[NetDev]
Name=dummy-test
Kind=dummy
MACAddress=12:34:56:78:9a:bc</programlisting>
    </example>

  </refsect1>
  <refsect1>
    <title>See Also</title>
    <para>
      <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.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
    </para>
  </refsect1>

</refentry>