summaryrefslogtreecommitdiff
path: root/man/systemd.network.xml
blob: 00fe83e30ba5bdf7093aa3255cad1667265bff27 (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
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
<?xml version='1.0'?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1+ -->

<refentry id="systemd.network" conditional='ENABLE_NETWORKD'>

  <refentryinfo>
    <title>systemd.network</title>
    <productname>systemd</productname>
  </refentryinfo>

  <refmeta>
    <refentrytitle>systemd.network</refentrytitle>
    <manvolnum>5</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>systemd.network</refname>
    <refpurpose>Network configuration</refpurpose>
  </refnamediv>

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

  <refsect1>
    <title>Description</title>

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

    <para>The main network file must have the extension <filename>.network</filename>; other
    extensions are ignored. Networks are applied to links whenever the links appear.</para>

    <para>The <filename>.network</filename> files are read from the files located in the system network
    directories <filename>/usr/lib/systemd/network</filename> and
    <filename>/usr/local/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 under
    <filename>/usr</filename>. This can be used to override a system-supplied configuration file with a local
    file if needed. As a special case, an empty file (file size 0) or symlink with the same name pointing to
    <filename>/dev/null</filename> disables the configuration file entirely (it is "masked").</para>

    <para>Along with the network file <filename>foo.network</filename>, a "drop-in" directory
    <filename>foo.network.d/</filename> may exist. All files with the suffix
    <literal>.conf</literal> from this directory will be parsed after the file itself is
    parsed. This is useful to alter or add configuration settings, without having to modify the main
    configuration file. Each drop-in file must have appropriate section headers.</para>

    <para>In addition to <filename>/etc/systemd/network</filename>, drop-in <literal>.d</literal>
    directories can be placed in <filename>/usr/lib/systemd/network</filename> or
    <filename>/run/systemd/network</filename> directories. Drop-in files in
    <filename>/etc</filename> take precedence over those in <filename>/run</filename> which in turn
    take precedence over those in <filename>/usr/lib</filename>. Drop-in files under any of these
    directories take precedence over the main netdev file wherever located.</para>

    <para>Note that an interface without any static IPv6 addresses configured, and neither DHCPv6
    nor IPv6LL enabled, shall be considered to have no IPv6 support. IPv6 will be automatically
    disabled for that interface by writing "1" to
    <filename>/proc/sys/net/ipv6/conf/<replaceable>ifname</replaceable>/disable_ipv6</filename>.
    </para>
  </refsect1>

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

      <para>The network file contains a <literal>[Match]</literal>
      section, which determines if a given network file may be applied
      to a given device; and a <literal>[Network]</literal> section
      specifying how the device should be configured. The first (in
      lexical order) of the network files that matches a given device
      is applied, all later files are ignored, even if they match as
      well.</para>

      <para>A network file is said to match a device if each of the
      entries in the <literal>[Match]</literal> section matches, or if
      the section is empty. The following keys are accepted:</para>

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>MACAddress=</varname></term>
          <listitem>
            <para>A whitespace-separated list of hardware addresses. Use full colon-, hyphen- or dot-delimited hexadecimal. See the example below.
            This option may appear more than one, in which case the lists are merged. If the empty string is assigned to this option, the list
            of hardware addresses defined prior to this is reset.</para>

            <para>Example:
            <programlisting>MACAddress=01:23:45:67:89:ab 00-11-22-33-44-55 AABB.CCDD.EEFF</programlisting></para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Path=</varname></term>
          <listitem>
            <para>A whitespace-separated list of shell-style globs
            matching the persistent path, as exposed by the udev
            property <literal>ID_PATH</literal>. If the list is
            prefixed with a "!", the test is inverted; i.e. it is
            true when <literal>ID_PATH</literal> does not match any
            item in the list.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Driver=</varname></term>
          <listitem>
            <para>A whitespace-separated list of shell-style globs
            matching the driver currently bound to the device, as
            exposed by the udev property <literal>DRIVER</literal>
            of its parent device, or if that is not set the driver
            as exposed by <literal>ethtool -i</literal> of the
            device itself. If the list is prefixed with a "!", the
            test is inverted.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Type=</varname></term>
          <listitem>
            <para>A whitespace-separated list of shell-style globs
            matching the device type, as exposed by the udev property
            <literal>DEVTYPE</literal>. If the list is prefixed with
            a "!", the test is inverted.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Name=</varname></term>
          <listitem>
            <para>A whitespace-separated list of shell-style globs
            matching the device name, as exposed by the udev property
            <literal>INTERFACE</literal>. If the list is prefixed
            with a "!", the test is inverted.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Host=</varname></term>
          <listitem>
            <para>Matches against the hostname or machine ID of the
            host. See <literal>ConditionHost=</literal> in
            <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
            for details.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Virtualization=</varname></term>
          <listitem>
            <para>Checks whether the system is executed in a virtualized
            environment and optionally test whether it is a specific
            implementation. See <literal>ConditionVirtualization=</literal> in
            <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
            for details.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>KernelCommandLine=</varname></term>
          <listitem>
            <para>Checks whether a specific kernel command line option is
            set (or if prefixed with the exclamation mark unset). See
            <literal>ConditionKernelCommandLine=</literal> in
            <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
            for details.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>KernelVersion=</varname></term>
          <listitem>
            <para>Checks whether the kernel version (as reported by <command>uname -r</command>) matches a certain
            expression (or if prefixed with the exclamation mark does not match it). See
            <literal>ConditionKernelVersion=</literal> in
            <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
            details.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Architecture=</varname></term>
          <listitem>
            <para>Checks whether the system is running on a specific
            architecture. See <literal>ConditionArchitecture=</literal> in
            <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
            for details.
            </para>
          </listitem>
        </varlistentry>
      </variablelist>

  </refsect1>

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

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

    <variablelist class='network-directives'>
      <varlistentry>
        <term><varname>MACAddress=</varname></term>
        <listitem>
          <para>The hardware address to set for the device.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>MTUBytes=</varname></term>
        <listitem>
          <para>The maximum transmission unit in bytes to set for the
          device. The usual suffixes K, M, G, are supported and are
          understood to the base of 1024.</para>
          <para>Note that if IPv6 is enabled on the interface, and the MTU is chosen
          below 1280 (the minimum MTU for IPv6) it will automatically be increased to this value.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>ARP=</varname></term>
        <listitem>
          <para>Takes a boolean. If set to true, the ARP (low-level Address Resolution Protocol)
          for this interface is enabled. When unset, the kernel's default will be used.</para>
          <para> For example, disabling ARP is useful when creating multiple MACVLAN or VLAN virtual
          interfaces atop a single lower-level physical interface, which will then only serve as a
          link/"bridge" device aggregating traffic to the same physical link and not participate in
          the network otherwise.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Multicast=</varname></term>
        <listitem>
          <para>Takes a boolean. If set to true, the multicast flag on the device is enabled.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>AllMulticast=</varname></term>
        <listitem>
          <para>Takes a boolean. If set to true, the driver retrieves all multicast packets from the network.
          This happens when multicast routing is enabled.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Unmanaged=</varname></term>
        <listitem>
          <para>Takes a boolean. When <literal>yes</literal>, no attempts are
          made to bring up or configure matching links, equivalent to
          when there are no matching network files. Defaults to
          <literal>no</literal>.</para>
          <para>This is useful for preventing later matching network
          files from interfering with certain interfaces that are fully
          controlled by other applications.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>RequiredForOnline=</varname></term>
        <listitem>
          <para>Takes a boolean or operational state. Please see
          <citerefentry><refentrytitle>networkctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
          for possible operational states. When <literal>yes</literal>, the network is deemed required when
          determining whether the system is online when running
          <command>systemd-networkd-wait-online</command>. When <literal>no</literal>, the network is ignored
          when checking for online state. When an operational state is set, <literal>yes</literal> is implied,
          and this controls the operational state required for the network interface to be considered online.
          Defaults to <literal>yes</literal>.</para>

          <para>The network will be brought up normally in all cases, but in
          the event that there is no address being assigned by DHCP or the
          cable is not plugged in, the link will simply remain offline and be
          skipped automatically by <command>systemd-networkd-wait-online</command>
          if <literal>RequiredForOnline=no</literal>.</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

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

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

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>Description=</varname></term>
          <listitem>
            <para>A description of the device. This is only used for
            presentation purposes.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>DHCP=</varname></term>
          <listitem>
            <para>Enables DHCPv4 and/or DHCPv6 client support. Accepts
            <literal>yes</literal>, <literal>no</literal>,
            <literal>ipv4</literal>, or <literal>ipv6</literal>. Defaults
            to <literal>no</literal>.</para>

            <para>Note that DHCPv6 will by default be triggered by Router
            Advertisement, if that is enabled, regardless of this parameter.
            By enabling DHCPv6 support explicitly, the DHCPv6 client will
            be started regardless of the presence of routers on the link,
            or what flags the routers pass. See
            <literal>IPv6AcceptRA=</literal>.</para>

            <para>Furthermore, note that by default the domain name
            specified through DHCP is not used for name resolution.
            See option <option>UseDomains=</option> below.</para>

            <para>See the <literal>[DHCP]</literal> section below for further configuration options for the DHCP client
            support.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>DHCPServer=</varname></term>
          <listitem>
            <para>Takes a boolean. If set to <literal>yes</literal>, DHCPv4 server will be started. Defaults
            to <literal>no</literal>. Further settings for the DHCP
            server may be set in the <literal>[DHCPServer]</literal>
            section described below.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>LinkLocalAddressing=</varname></term>
          <listitem>
            <para>Enables link-local address autoconfiguration. Accepts <literal>yes</literal>,
            <literal>no</literal>, <literal>ipv4</literal>, or <literal>ipv6</literal>. If
            <varname>Bridge=</varname> is set, defaults to <literal>no</literal>, and if not,
            defaults to <literal>ipv6</literal>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IPv4LLRoute=</varname></term>
          <listitem>
            <para>Takes a boolean. If set to true, sets up the route needed for
            non-IPv4LL hosts to communicate with IPv4LL-only hosts. Defaults
            to false.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IPv6Token=</varname></term>
          <listitem>
            <para>An IPv6 address with the top 64 bits unset. When set, indicates the
            64-bit interface part of SLAAC IPv6 addresses for this link. Note that
            the token is only ever used for SLAAC, and not for DHCPv6 addresses, even
            in the case DHCP is requested by router advertisement. By default, the
            token is autogenerated.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>LLMNR=</varname></term>
          <listitem>
            <para>Takes a boolean or <literal>resolve</literal>. When true,
            enables <ulink
            url="https://tools.ietf.org/html/rfc4795">Link-Local
            Multicast Name Resolution</ulink> on the link. When set to
            <literal>resolve</literal>, only resolution is enabled,
            but not host registration and announcement. Defaults to
            true. This setting is read by
            <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>MulticastDNS=</varname></term>
          <listitem>
            <para>Takes a boolean or <literal>resolve</literal>. When true,
            enables <ulink
            url="https://tools.ietf.org/html/rfc6762">Multicast
            DNS</ulink> support on the link. When set to
            <literal>resolve</literal>, only resolution is enabled,
            but not host or service registration and
            announcement. Defaults to false. This setting is read by
            <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>DNSOverTLS=</varname></term>
          <listitem>
            <para>Takes false or
            <literal>opportunistic</literal>. When set to <literal>opportunistic</literal>, enables
            <ulink
            url="https://tools.ietf.org/html/rfc7858">DNS-over-TLS</ulink>
            support on the link. This option defines a
            per-interface setting for
            <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s
            global <varname>DNSOverTLS=</varname> option. Defaults to
            false. This setting is read by
            <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>DNSSEC=</varname></term>
          <listitem>
            <para>Takes a boolean. or
            <literal>allow-downgrade</literal>. When true, enables
            <ulink
            url="https://tools.ietf.org/html/rfc4033">DNSSEC</ulink>
            DNS validation support on the link. When set to
            <literal>allow-downgrade</literal>, compatibility with
            non-DNSSEC capable networks is increased, by automatically
            turning off DNSSEC in this case. This option defines a
            per-interface setting for
            <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s
            global <varname>DNSSEC=</varname> option. Defaults to
            false. This setting is read by
            <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>DNSSECNegativeTrustAnchors=</varname></term>
          <listitem><para>A space-separated list of DNSSEC negative
          trust anchor domains. If specified and DNSSEC is enabled,
          look-ups done via the interface's DNS server will be subject
          to the list of negative trust anchors, and not require
          authentication for the specified domains, or anything below
          it. Use this to disable DNSSEC authentication for specific
          private domains, that cannot be proven valid using the
          Internet DNS hierarchy. Defaults to the empty list. This
          setting is read by
          <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>LLDP=</varname></term>
          <listitem>
            <para>Controls support for Ethernet LLDP packet reception. LLDP is a link-layer protocol commonly
            implemented on professional routers and bridges which announces which physical port a system is connected
            to, as well as other related data. Accepts a boolean or the special value
            <literal>routers-only</literal>. When true, incoming LLDP packets are accepted and a database of all LLDP
            neighbors maintained. If <literal>routers-only</literal> is set only LLDP data of various types of routers
            is collected and LLDP data about other types of devices ignored (such as stations, telephones and
            others). If false, LLDP reception is disabled. Defaults to <literal>routers-only</literal>. Use
            <citerefentry><refentrytitle>networkctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> to query the
            collected neighbor data. LLDP is only available on Ethernet links. See <varname>EmitLLDP=</varname> below
            for enabling LLDP packet emission from the local system.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>EmitLLDP=</varname></term>
          <listitem>
            <para>Controls support for Ethernet LLDP packet emission. Accepts a boolean parameter or the special values
            <literal>nearest-bridge</literal>, <literal>non-tpmr-bridge</literal> and
            <literal>customer-bridge</literal>.  Defaults to false, which turns off LLDP packet emission. If not false,
            a short LLDP packet with information about the local system is sent out in regular intervals on the
            link. The LLDP packet will contain information about the local host name, the local machine ID (as stored
            in <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>) and the
            local interface name, as well as the pretty hostname of the system (as set in
            <citerefentry><refentrytitle>machine-info</refentrytitle><manvolnum>5</manvolnum></citerefentry>). LLDP
            emission is only available on Ethernet links. Note that this setting passes data suitable for
            identification of host to the network and should thus not be enabled on untrusted networks, where such
            identification data should not be made available. Use this option to permit other systems to identify on
            which interfaces they are connected to this system. The three special values control propagation of the
            LLDP packets. The <literal>nearest-bridge</literal> setting permits propagation only to the nearest
            connected bridge, <literal>non-tpmr-bridge</literal> permits propagation across Two-Port MAC Relays, but
            not any other bridges, and <literal>customer-bridge</literal> permits propagation until a customer bridge
            is reached. For details about these concepts, see <ulink
            url="https://standards.ieee.org/findstds/standard/802.1AB-2016.html">IEEE 802.1AB-2016</ulink>. Note that
            configuring this setting to true is equivalent to <literal>nearest-bridge</literal>, the recommended and
            most restricted level of propagation. See <varname>LLDP=</varname> above for an option to enable LLDP
            reception.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>BindCarrier=</varname></term>
          <listitem>
            <para>A link name or a list of link names. When set, controls the behavior of the current
            link. When all links in the list are in an operational down state, the current link is brought
            down. When at least one link has carrier, the current interface is brought up.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Address=</varname></term>
          <listitem>
            <para>A static IPv4 or IPv6 address and its prefix length,
            separated by a <literal>/</literal> character. Specify
            this key more than once to configure several addresses.
            The format of the address must be as described in
            <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
            This is a short-hand for an [Address] section only
            containing an Address key (see below). This option may be
            specified more than once.
            </para>

            <para>If the specified address is <literal>0.0.0.0</literal> (for IPv4) or <literal>::</literal>
            (for IPv6), a new address range of the requested size is automatically allocated from a
            system-wide pool of unused ranges. Note that the prefix length must be equal or larger than 8 for
            IPv4, and 64 for IPv6. The allocated range is checked against all current network interfaces and
            all known network configuration files to avoid address range conflicts. The default system-wide
            pool consists of 192.168.0.0/16, 172.16.0.0/12 and 10.0.0.0/8 for IPv4, and fd00::/8 for IPv6.
            This functionality is useful to manage a large number of dynamically created network interfaces
            with the same network configuration and automatic address range assignment.</para>

          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Gateway=</varname></term>
          <listitem>
            <para>The gateway address, which must be in the format
            described in
            <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
            This is a short-hand for a [Route] section only containing
            a Gateway key. This option may be specified more than
            once.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>DNS=</varname></term>
          <listitem>
            <para>A DNS server address, which must be in the format
            described in
            <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
            This option may be specified more than once. This setting is read by
            <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Domains=</varname></term>
          <listitem>
            <para>A list of domains which should be resolved using the DNS servers on this link. Each item in the list
            should be a domain name, optionally prefixed with a tilde (<literal>~</literal>). The domains with the
            prefix are called "routing-only domains". The domains without the prefix are called "search domains" and
            are first used as search suffixes for extending single-label host names (host names containing no dots) to
            become fully qualified domain names (FQDNs). If a single-label host name is resolved on this interface,
            each of the specified search domains are appended to it in turn, converting it into a fully qualified
            domain name, until one of them may be successfully resolved.</para>

            <para>Both "search" and "routing-only" domains are used for routing of DNS queries: look-ups for host names
            ending in those domains (hence also single label names, if any "search domains" are listed), are routed to
            the DNS servers configured for this interface. The domain routing logic is particularly useful on
            multi-homed hosts with DNS servers serving particular private DNS zones on each interface.</para>

            <para>The "routing-only" domain <literal>~.</literal> (the tilde indicating definition of a routing domain,
            the dot referring to the DNS root domain which is the implied suffix of all valid DNS names) has special
            effect. It causes all DNS traffic which does not match another configured domain routing entry to be routed
            to DNS servers specified for this interface. This setting is useful to prefer a certain set of DNS servers
            if a link on which they are connected is available.</para>

            <para>This setting is read by
            <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
            "Search domains" correspond to the <varname>domain</varname> and <varname>search</varname> entries in
            <citerefentry project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
            Domain name routing has no equivalent in the traditional glibc API, which has no concept of domain
            name servers limited to a specific link.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>DNSDefaultRoute=</varname></term>
          <listitem>
            <para>Takes a boolean argument. If true, this link's configured DNS servers are used for resolving domain
            names that do not match any link's configured <varname>Domains=</varname> setting. If false, this link's
            configured DNS servers are never used for such domains, and are exclusively used for resolving names that
            match at least one of the domains configured on this link. If not specified defaults to an automatic mode:
            queries not matching any link's configured domains will be routed to this link if it has no routing-only
            domains configured.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>NTP=</varname></term>
          <listitem>
            <para>An NTP server address. This option may be specified more than once. This setting is read by
            <citerefentry><refentrytitle>systemd-timesyncd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IPForward=</varname></term>
          <listitem><para>Configures IP packet forwarding for the
          system. If enabled, incoming packets on any network
          interface will be forwarded to any other interfaces
          according to the routing table. Takes a boolean,
          or the values <literal>ipv4</literal> or
          <literal>ipv6</literal>, which only enable IP packet
          forwarding for the specified address family.  This controls
          the <filename>net.ipv4.ip_forward</filename> and
          <filename>net.ipv6.conf.all.forwarding</filename> sysctl
          options of the network interface (see <ulink
          url="https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt</ulink>
          for details about sysctl options). Defaults to
          <literal>no</literal>.</para>

          <para>Note: this setting controls a global kernel option,
          and does so one way only: if a network that has this setting
          enabled is set up the global setting is turned on.  However,
          it is never turned off again, even after all networks with
          this setting enabled are shut down again.</para>

          <para>To allow IP packet forwarding only between specific
          network interfaces use a firewall.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IPMasquerade=</varname></term>
          <listitem><para>Configures IP masquerading for the network
          interface. If enabled, packets forwarded from the network
          interface will be appear as coming from the local host.
          Takes a boolean argument. Implies
          <varname>IPForward=ipv4</varname>. Defaults to
          <literal>no</literal>.</para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IPv6PrivacyExtensions=</varname></term>
          <listitem><para>Configures use of stateless temporary
          addresses that change over time (see <ulink
          url="https://tools.ietf.org/html/rfc4941">RFC 4941</ulink>,
          Privacy Extensions for Stateless Address Autoconfiguration
          in IPv6). Takes a boolean or the special values
          <literal>prefer-public</literal> and
          <literal>kernel</literal>. When true, enables the privacy
          extensions and prefers temporary addresses over public
          addresses. When <literal>prefer-public</literal>, enables the
          privacy extensions, but prefers public addresses over
          temporary addresses. When false, the privacy extensions
          remain disabled. When <literal>kernel</literal>, the kernel's
          default setting will be left in place.  Defaults to
          <literal>no</literal>.</para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IPv6AcceptRA=</varname></term>
          <listitem><para>Takes a boolean. Controls IPv6 Router Advertisement (RA) reception support for the interface.
          If true, RAs are accepted; if false, RAs are ignored, independently of the local forwarding state.
          If unset, the kernel's default is used, and RAs are accepted only when local forwarding
          is disabled for that interface.  When RAs are accepted, they may trigger the start of the DHCPv6 client if
          the relevant flags are set in the RA data, or if no routers are found on the link.</para>

          <para>Further settings for the IPv6 RA support may be configured in the
          <literal>[IPv6AcceptRA]</literal> section, see below.</para>

          <para>Also see <ulink
          url="https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt</ulink> in the kernel
          documentation regarding <literal>accept_ra</literal>, but note that systemd's setting of
          <constant>1</constant> (i.e. true) corresponds to kernel's setting of <constant>2</constant>.</para>
        </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IPv6DuplicateAddressDetection=</varname></term>
          <listitem><para>Configures the amount of IPv6 Duplicate
          Address Detection (DAD) probes to send. When unset, the kernel's default will be used.
        </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IPv6HopLimit=</varname></term>
          <listitem><para>Configures IPv6 Hop Limit. For each router that
          forwards the packet, the hop limit is decremented by 1. When the
          hop limit field reaches zero, the packet is discarded.
          When unset, the kernel's default will be used.
        </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IPv4ProxyARP=</varname></term>
          <listitem><para>Takes a boolean. Configures proxy ARP for IPv4. Proxy ARP is the technique in which one host,
          usually a router, answers ARP requests intended for another machine. By "faking" its identity,
          the router accepts responsibility for routing packets to the "real" destination. (see <ulink
          url="https://tools.ietf.org/html/rfc1027">RFC 1027</ulink>.
          When unset, the kernel's default will be used.
        </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IPv6ProxyNDP=</varname></term>
          <listitem><para>Takes a boolean. Configures proxy NDP for IPv6. Proxy NDP (Neighbor Discovery
          Protocol) is a technique for IPv6 to allow routing of addresses to a different
          destination when peers expect them to be present on a certain physical link.
          In this case a router answers Neighbour Advertisement messages intended for
          another machine by offering its own MAC address as destination.
          Unlike proxy ARP for IPv4, it is not enabled globally, but will only send Neighbour
          Advertisement messages for addresses in the IPv6 neighbor proxy table,
          which can also be shown by <command>ip -6 neighbour show proxy</command>.
          systemd-networkd will control the per-interface `proxy_ndp` switch for each configured
          interface depending on this option.
          When unset, the kernel's default will be used.
        </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IPv6ProxyNDPAddress=</varname></term>
          <listitem><para>An IPv6 address, for which Neighbour Advertisement messages will be
          proxied. This option may be specified more than once. systemd-networkd will add the
          <option>IPv6ProxyNDPAddress=</option> entries to the kernel's IPv6 neighbor proxy table.
          This option implies <option>IPv6ProxyNDP=yes</option> but has no effect if
          <option>IPv6ProxyNDP</option> has been set to false. When unset, the kernel's default will be used.
        </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IPv6PrefixDelegation=</varname></term>
          <listitem><para>Whether to enable or disable Router Advertisement sending on a link.
          Allowed values are <literal>static</literal> which distributes prefixes as defined in
          the <literal>[IPv6PrefixDelegation]</literal> and any <literal>[IPv6Prefix]</literal>
          sections, <literal>dhcpv6</literal> which requests prefixes using a DHCPv6 client
          configured for another link and any values configured in the
          <literal>[IPv6PrefixDelegation]</literal> section while ignoring all static prefix
          configuration sections, <literal>yes</literal> which uses both static configuration
          and DHCPv6, and <literal>false</literal> which turns off IPv6 prefix delegation
          altogether. Defaults to <literal>false</literal>. See the
          <literal>[IPv6PrefixDelegation]</literal> and the <literal>[IPv6Prefix]</literal>
          sections for more configuration options.
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IPv6MTUBytes=</varname></term>
          <listitem><para>Configures IPv6 maximum transmission unit (MTU).
          An integer greater than or equal to 1280 bytes. When unset, the kernel's default will be used.
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Bridge=</varname></term>
          <listitem>
            <para>The name of the bridge to add the link to. See
            <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Bond=</varname></term>
          <listitem>
            <para>The name of the bond to add the link to. See
            <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>VRF=</varname></term>
          <listitem>
            <para>The name of the VRF to add the link to. See
            <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>VLAN=</varname></term>
          <listitem>
            <para>The name of a VLAN to create on the link. See
            <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
            This option may be specified more than once.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IPVLAN=</varname></term>
          <listitem>
            <para>The name of a IPVLAN to create on the link. See
            <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
            This option may be specified more than once.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>MACVLAN=</varname></term>
          <listitem>
            <para>The name of a MACVLAN to create on the link. See
            <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
            This option may be specified more than once.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>VXLAN=</varname></term>
          <listitem>
            <para>The name of a VXLAN to create on the link. See
            <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
            This option may be specified more than once.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Tunnel=</varname></term>
          <listitem>
            <para>The name of a Tunnel to create on the link. See
            <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
            This option may be specified more than once.</para>
          </listitem>
        </varlistentry>
      <varlistentry>
        <term><varname>ActiveSlave=</varname></term>
        <listitem>
          <para>Takes a boolean. Specifies the new active slave. The <literal>ActiveSlave=</literal>
          option is only valid for following modes:
          <literal>active-backup</literal>,
          <literal>balance-alb</literal> and
          <literal>balance-tlb</literal>. Defaults to false.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>PrimarySlave=</varname></term>
        <listitem>
          <para>Takes a boolean. Specifies which slave is the primary device. The specified
          device will always be the active slave while it is available. Only when the
          primary is off-line will alternate devices be used.  This is useful when
          one slave is preferred over another, e.g. when one slave has higher throughput
          than another. The <literal>PrimarySlave=</literal> option is only valid for
          following modes:
          <literal>active-backup</literal>,
          <literal>balance-alb</literal> and
          <literal>balance-tlb</literal>. Defaults to false.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>ConfigureWithoutCarrier=</varname></term>
        <listitem>
          <para>Takes a boolean. Allows networkd to configure a specific link even if it has no carrier.
          Defaults to false.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>IgnoreCarrierLoss=</varname></term>
        <listitem>
          <para>A boolean. Allows networkd to retain both the static and dynamic configuration of the
          interface even if its carrier is lost. Defaults to false.
          </para>
        </listitem>
      </varlistentry>

      </variablelist>

  </refsect1>

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

      <para>An <literal>[Address]</literal> section accepts the
      following keys. Specify several <literal>[Address]</literal>
      sections to configure several addresses.</para>

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>Address=</varname></term>
          <listitem>
            <para>As in the <literal>[Network]</literal> section. This key is mandatory. Each
            <literal>[Address]</literal> section can contain one <varname>Address=</varname> setting.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Peer=</varname></term>
          <listitem>
            <para>The peer address in a point-to-point connection.
            Accepts the same format as the <varname>Address=</varname>
            key.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Broadcast=</varname></term>
          <listitem>
            <para>The broadcast address, which must be in the format
            described in
            <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
            This key only applies to IPv4 addresses. If it is not
            given, it is derived from the <varname>Address=</varname>
            key.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Label=</varname></term>
          <listitem>
            <para>An address label.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>PreferredLifetime=</varname></term>
          <listitem>
            <para>Allows the default "preferred lifetime" of the address to be overridden.
            Only three settings are accepted: <literal>forever</literal> or <literal>infinity</literal>
            which is the default and means that the address never expires, and <literal>0</literal> which means
            that the address is considered immediately "expired" and will not be used,
            unless explicitly requested. A setting of PreferredLifetime=0 is useful for
            addresses which are added to be used only by a specific application,
            which is then configured to use them explicitly.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Scope=</varname></term>
          <listitem>
            <para>The scope of the address, which can be <literal>global</literal>,
            <literal>link</literal> or <literal>host</literal> or an unsigned integer ranges 0 to 255.
            Defaults to <literal>global</literal>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>HomeAddress=</varname></term>
          <listitem>
            <para>Takes a boolean. Designates this address the "home address" as defined in
            <ulink url="https://tools.ietf.org/html/rfc6275">RFC 6275</ulink>.
            Supported only on IPv6. Defaults to false.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>DuplicateAddressDetection=</varname></term>
          <listitem>
            <para>Takes a boolean. Do not perform Duplicate Address Detection
            <ulink url="https://tools.ietf.org/html/rfc4862">RFC 4862</ulink> when adding this address.
            Supported only on IPv6. Defaults to false.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>ManageTemporaryAddress=</varname></term>
          <listitem>
            <para>Takes a boolean. If true the kernel manage temporary addresses created
            from this one as template on behalf of Privacy Extensions
            <ulink url="https://tools.ietf.org/html/rfc3041">RFC 3041</ulink>.  For this to become
            active, the use_tempaddr sysctl setting has to be set to a value greater than zero.
            The given address needs to have a prefix length of 64. This flag allows to use privacy
            extensions in a manually configured network, just like if stateless auto-configuration
            was active. Defaults to false. </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>PrefixRoute=</varname></term>
          <listitem>
            <para>Takes a boolean. When adding or modifying an IPv6 address, the userspace
            application needs a way to suppress adding a prefix route. This is for example relevant
            together with IFA_F_MANAGERTEMPADDR, where userspace creates autoconf generated addresses,
            but depending on on-link, no route for the prefix should be added. Defaults to false.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>AutoJoin=</varname></term>
          <listitem>
            <para>Takes a boolean. Joining multicast group on ethernet level via
            <command>ip maddr</command> command would not work if we have an Ethernet switch that does
            IGMP snooping since the switch would not replicate multicast packets on  ports that did not
            have IGMP reports for the multicast addresses. Linux vxlan interfaces created via
            <command>ip link add vxlan</command> or networkd's netdev kind vxlan have the group option
            that enables then to do the required join. By extending ip address command with option
            <literal>autojoin</literal> we can get similar functionality for openvswitch (OVS) vxlan
            interfaces as well as other tunneling mechanisms that need to receive multicast traffic.
            Defaults to <literal>no</literal>.</para>
          </listitem>
        </varlistentry>
      </variablelist>
  </refsect1>

  <refsect1>
    <title>[Neighbor] Section Options</title>
      <para>A <literal>[Neighbor]</literal> section accepts the
      following keys. The neighbor section adds a permanent, static
      entry to the neighbor table (IPv6) or ARP table (IPv4) for
      the given hardware address on the links matched for the network.
      Specify several <literal>[Neighbor]</literal> sections to configure
      several static neighbors.</para>

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>Address=</varname></term>
          <listitem>
            <para>The IP address of the neighbor.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>MACAddress=</varname></term>
          <listitem>
            <para>The hardware address of the neighbor.</para>
          </listitem>
        </varlistentry>
      </variablelist>
  </refsect1>

    <refsect1>
    <title>[IPv6AddressLabel] Section Options</title>

      <para>An <literal>[IPv6AddressLabel]</literal> section accepts the
      following keys. Specify several <literal>[IPv6AddressLabel]</literal>
      sections to configure several address labels. IPv6 address labels are
      used for address selection. See <ulink url="https://tools.ietf.org/html/rfc3484">RFC 3484</ulink>.
      Precedence is managed by userspace, and only the label itself is stored in the kernel</para>

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>Label=</varname></term>
          <listitem>
            <para> The label for the prefix (an unsigned integer) ranges 0 to 4294967294.
            0xffffffff is reserved. This key is mandatory.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Prefix=</varname></term>
          <listitem>
            <para>IPv6 prefix is an address with a prefix length, separated by a slash <literal>/</literal> character.
            This key is mandatory. </para>
          </listitem>
        </varlistentry>
      </variablelist>
  </refsect1>

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

      <para>An <literal>[RoutingPolicyRule]</literal> section accepts the
      following keys. Specify several <literal>[RoutingPolicyRule]</literal>
      sections to configure several rules.</para>

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>TypeOfService=</varname></term>
          <listitem>
            <para>Specifies the type of service to match a number between 0 to 255.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>From=</varname></term>
          <listitem>
            <para>Specifies the source address prefix to match. Possibly followed by a slash and the prefix length.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>To=</varname></term>
          <listitem>
            <para>Specifies the destination address prefix to match. Possibly followed by a slash and the prefix length.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>FirewallMark=</varname></term>
          <listitem>
            <para>Specifies the iptables firewall mark value to match (a number between 1 and 4294967295).</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Table=</varname></term>
          <listitem>
            <para>Specifies the routing table identifier to lookup if the rule
            selector matches. The table identifier for a route (a number between 1 and 4294967295).</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Priority=</varname></term>
          <listitem>
            <para>Specifies the priority of this rule. <varname>Priority=</varname> is an unsigned
            integer. Higher number means lower priority, and rules get processed in order of increasing number.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IncomingInterface=</varname></term>
          <listitem>
            <para>Specifies incoming device to match. If the interface is loopback, the rule only matches packets originating from this host.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>OutgoingInterface=</varname></term>
          <listitem>
            <para>Specifies the outgoing device to match. The outgoing interface is only available for packets originating from local sockets that are bound to a device.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>SourcePort=</varname></term>
          <listitem>
            <para>Specifies the source IP port or IP port range match in forwarding information base (FIB) rules.
            A port range is specified by the lower and upper port separated by a dash. Defaults to unset.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>DestinationPort=</varname></term>
          <listitem>
            <para>Specifies the destination IP port or IP port range match in forwarding information base (FIB) rules.
            A port range is specified by the lower and upper port separated by a dash. Defaults to unset.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IPProtocol=</varname></term>
          <listitem>
            <para>Specifies the IP protocol to match in forwarding information base (FIB) rules. Takes IP protocol name such as <literal>tcp</literal>,
            <literal>udp</literal> or <literal>sctp</literal>, or IP protocol number such as <literal>6</literal> for <literal>tcp</literal> or
            <literal>17</literal> for <literal>udp</literal>.
            Defaults to unset.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>InvertRule=</varname></term>
          <listitem>
            <para>A boolean. Specifies wheather the rule to be inverted. Defaults to false.</para>
          </listitem>
        </varlistentry>
      </variablelist>
  </refsect1>

  <refsect1>
    <title>[Route] Section Options</title>
      <para>The <literal>[Route]</literal> section accepts the
      following keys. Specify several <literal>[Route]</literal>
      sections to configure several routes.</para>

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>Gateway=</varname></term>
          <listitem>
            <para>As in the <literal>[Network]</literal> section.</para>
          </listitem>
        </varlistentry>
         <varlistentry>
           <term><varname>GatewayOnLink=</varname></term>
           <listitem>
             <para>Takes a boolean. If set to true, the kernel does not have
             to check if the gateway is reachable directly by the current machine (i.e., the kernel does
             not need to check if the gateway is attached to the local network), so that we can insert the
             route in the kernel table without it being complained about. Defaults to <literal>no</literal>.
             </para>
           </listitem>
         </varlistentry>
        <varlistentry>
          <term><varname>Destination=</varname></term>
          <listitem>
            <para>The destination prefix of the route. Possibly
            followed by a slash and the prefix length. If omitted, a
            full-length host route is assumed.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Source=</varname></term>
          <listitem>
            <para>The source prefix of the route. Possibly followed by
            a slash and the prefix length. If omitted, a full-length
            host route is assumed.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Metric=</varname></term>
          <listitem>
            <para>The metric of the route (an unsigned integer).</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IPv6Preference=</varname></term>
          <listitem>
            <para>Specifies the route preference as defined in <ulink
            url="https://tools.ietf.org/html/rfc4191">RFC4191</ulink> for Router Discovery messages.
            Which can be one of <literal>low</literal> the route has a lowest priority,
            <literal>medium</literal> the route has a default priority or
            <literal>high</literal> the route has a highest priority.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Scope=</varname></term>
          <listitem>
            <para>The scope of the route, which can be <literal>global</literal>,
            <literal>link</literal> or <literal>host</literal>. Defaults to
            <literal>global</literal>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>PreferredSource=</varname></term>
          <listitem>
            <para>The preferred source address of the route. The address
            must be in the format described in
            <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Table=<replaceable>num</replaceable></varname></term>
          <listitem>
          <para>The table identifier for the route (a number between 1 and 4294967295, or 0 to unset).
          The table can be retrieved using <command>ip route show table <replaceable>num</replaceable></command>.
          </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Protocol=</varname></term>
          <listitem>
            <para>The protocol identifier for the route. Takes a number between 0 and 255 or the special values
            <literal>kernel</literal>, <literal>boot</literal> and <literal>static</literal>. Defaults to
            <literal>static</literal>.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Type=</varname></term>
          <listitem>
            <para>Specifies the type for the route. If <literal>unicast</literal>, a regular route is defined, i.e. a
            route indicating the path to take to a destination network address. If <literal>blackhole</literal>, packets
            to the defined route are discarded silently. If <literal>unreachable</literal>, packets to the defined route
            are discarded and the ICMP message "Host Unreachable" is generated. If <literal>prohibit</literal>, packets
            to the defined route are discarded and the ICMP message "Communication Administratively Prohibited" is
            generated. If <literal>throw</literal>, route lookup in the current routing table will fail and the route
            selection process will return to Routing Policy Database (RPDB). Defaults to <literal>unicast</literal>.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>InitialCongestionWindow=</varname></term>
          <listitem>
            <para>The TCP initial congestion window is used during the start of a TCP connection. During the start of a TCP
            session, when a client requests a resource, the server's initial congestion window determines how many data bytes
            will be sent during the initial burst of data. Takes a size in bytes between 1 and 4294967295 (2^32 - 1). The usual
            suffixes K, M, G are supported and are understood to the base of 1024. When unset, the kernel's default will be used.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>InitialAdvertisedReceiveWindow=</varname></term>
          <listitem>
            <para>The TCP initial advertised receive window is the amount of receive data (in bytes) that can initally be buffered at one time
            on a connection. The sending host can send only that amount of data before waiting for an acknowledgment and window update
            from the receiving host. Takes a size in bytes between 1 and 4294967295 (2^32 - 1). The usual suffixes K, M, G are supported
            and are understood to the base of 1024. When unset, the kernel's default will be used.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>QuickAck=</varname></term>
          <listitem>
            <para>Takes a boolean. When true enables TCP quick ack mode for the route. When unset, the kernel's default will be used.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
        <term><varname>MTUBytes=</varname></term>
        <listitem>
          <para>The maximum transmission unit in bytes to set for the
          route. The usual suffixes K, M, G, are supported and are
          understood to the base of 1024.</para>
          <para>Note that if IPv6 is enabled on the interface, and the MTU is chosen
          below 1280 (the minimum MTU for IPv6) it will automatically be increased to this value.</para>
        </listitem>
      </varlistentry>
      </variablelist>
  </refsect1>

  <refsect1>
    <title>[DHCP] Section Options</title>
      <para>The <literal>[DHCP]</literal> section configures the
      DHCPv4 and DHCP6 client, if it is enabled with the
      <varname>DHCP=</varname> setting described above:</para>

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>UseDNS=</varname></term>
          <listitem>
            <para>When true (the default), the DNS servers received
            from the DHCP server will be used and take precedence over
            any statically configured ones.</para>

            <para>This corresponds to the <option>nameserver</option>
            option in <citerefentry
            project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>UseNTP=</varname></term>
          <listitem>
            <para>When true (the default), the NTP servers received
            from the DHCP server will be used by systemd-timesyncd
            and take precedence over any statically configured ones.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>UseMTU=</varname></term>
          <listitem>
            <para>When true, the interface maximum transmission unit
            from the DHCP server will be used on the current link.
            If <varname>MTUBytes=</varname> is set, then this setting is ignored.
            Defaults to false.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Anonymize=</varname></term>
          <listitem>
            <para>Takes a boolean. When true, the options sent to the DHCP server will
            follow the <ulink url="https://tools.ietf.org/html/rfc7844">RFC 7844</ulink>
            (Anonymity Profiles for DHCP Clients) to minimize disclosure of identifying information.
            Defaults to false.</para>

            <para>This option should only be set to true when
            <varname>MACAddressPolicy=</varname> is set to <literal>random</literal>
            (see <citerefentry
            project='man-pages'><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>).</para>

            <para>Note that this configuration will overwrite others.
            In concrete, the following variables will be ignored:
            <varname>SendHostname=</varname>, <varname>ClientIdentifier=</varname>,
            <varname>UseRoutes=</varname>, <varname>SendHostname=</varname>,
            <varname>UseMTU=</varname>, <varname>VendorClassIdentifier=</varname>,
            <varname>UseTimezone=</varname>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>SendHostname=</varname></term>
          <listitem>
            <para>When true (the default), the machine's hostname will be sent to the DHCP server.
            Note that the machine's hostname must consist only of 7-bit ASCII lower-case characters and
            no spaces or dots, and be formatted as a valid DNS domain name. Otherwise, the hostname is not
            sent even if this is set to true.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>UseHostname=</varname></term>
          <listitem>
            <para>When true (the default), the hostname received from
            the DHCP server will be set as the transient hostname of the system.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Hostname=</varname></term>
          <listitem>
            <para>Use this value for the hostname which is sent to the DHCP server, instead of machine's hostname.
            Note that the specified hostname must consist only of 7-bit ASCII lower-case characters and
            no spaces or dots, and be formatted as a valid DNS domain name.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>UseDomains=</varname></term>
          <listitem>
            <para>Takes a boolean, or the special value <literal>route</literal>. When true, the domain name
            received from the DHCP server will be used as DNS search domain over this link, similar to the effect of
            the <option>Domains=</option> setting. If set to <literal>route</literal>, the domain name received from
            the DHCP server will be used for routing DNS queries only, but not for searching, similar to the effect of
            the <option>Domains=</option> setting when the argument is prefixed with <literal>~</literal>. Defaults to
            false.</para>

            <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
            of all host names, in particular of single-label names. It is generally safer to use the supplied domain
            only as routing domain, rather than as search domain, in order to not have it affect local resolution of
            single-label names.</para>

            <para>When set to true, this setting corresponds to the <option>domain</option> option in <citerefentry
            project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>UseRoutes=</varname></term>
          <listitem>
            <para>When true (the default), the static routes will be requested from the DHCP server and added to the
              routing table with a metric of 1024, and a scope of "global", "link" or "host", depending on the route's
              destination and gateway. If the destination is on the local host, e.g., 127.x.x.x, or the same as the
              link's own address, the scope will be set to "host". Otherwise if the gateway is null (a direct route), a
              "link" scope will be used. For anything else, scope defaults to "global".</para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>UseTimezone=</varname></term>

          <listitem><para>When true, the timezone received from the
          DHCP server will be set as timezone of the local
          system. Defaults to <literal>no</literal>.</para></listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>CriticalConnection=</varname></term>
          <listitem>
            <para>When true, the connection will never be torn down
            even if the DHCP lease expires. This is contrary to the
            DHCP specification, but may be the best choice if, say,
            the root filesystem relies on this connection. Defaults to
            false.</para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>ClientIdentifier=</varname></term>
          <listitem>
            <para>The DHCPv4 client identifier to use. Takes one of <literal>mac</literal>, <literal>duid</literal> or <literal>duid-only</literal>.
            If set to <literal>mac</literal>, the MAC address of the link is used.
            If set to <literal>duid</literal>, an RFC4361-compliant Client ID, which is the combination of IAID and DUID (see below), is used.
            If set to <literal>duid-only</literal>, only DUID is used, this may not be RFC compliant, but some setups may require to use this.
            Defaults to <literal>duid</literal>.</para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>VendorClassIdentifier=</varname></term>
          <listitem>
            <para>The vendor class identifier used to identify vendor
            type and configuration.</para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>UserClass=</varname></term>
          <listitem>
            <para>A DHCPv4 client can use UserClass option to identify the type or category of user or applications
            it represents. The information contained in this option is a string that represents the user class of which
            the client is a member. Each class sets an identifying string of information to be used by the DHCP
            service to classify clients. Takes a whitespace-separated list of strings.</para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>DUIDType=</varname></term>
          <listitem>
            <para>Override the global <varname>DUIDType</varname> setting for this network. See
            <citerefentry><refentrytitle>networkd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
            for a description of possible values.</para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>DUIDRawData=</varname></term>
          <listitem>
            <para>Override the global <varname>DUIDRawData</varname> setting for this network. See
            <citerefentry><refentrytitle>networkd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
            for a description of possible values.</para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>IAID=</varname></term>
          <listitem>
            <para>The DHCP Identity Association Identifier (IAID) for the interface, a 32-bit unsigned integer.</para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>RequestBroadcast=</varname></term>
          <listitem>
            <para>Request the server to use broadcast messages before
            the IP address has been configured. This is necessary for
            devices that cannot receive RAW packets, or that cannot
            receive packets at all before an IP address has been
            configured. On the other hand, this must not be enabled on
            networks where broadcasts are filtered out.</para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>RouteMetric=</varname></term>
          <listitem>
            <para>Set the routing metric for routes specified by the
            DHCP server.</para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>RouteTable=<replaceable>num</replaceable></varname></term>
          <listitem>
            <para>The table identifier for DHCP routes (a number between 1 and 4294967295, or 0 to unset).
            The table can be retrieved using <command>ip route show table <replaceable>num</replaceable></command>.
            </para>
            <para>When used in combination with <varname>VRF=</varname> the
            VRF's routing table is used unless this parameter is specified.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>ListenPort=</varname></term>
          <listitem>
            <para>Allow setting custom port for the DHCP client to listen on.</para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>RapidCommit=</varname></term>
          <listitem>
            <para>Takes a boolean. The DHCPv6 client can obtain configuration parameters from a DHCPv6 server through
            a rapid two-message exchange (solicit and reply). When the rapid commit option is enabled by both
            the DHCPv6 client and the DHCPv6 server, the two-message exchange is used, rather than the default
            four-method exchange (solicit, advertise, request, and reply). The two-message exchange provides
            faster client configuration and is beneficial in environments in which networks are under a heavy load.
            See <ulink url="https://tools.ietf.org/html/rfc3315#section-17.2.1">RFC 3315</ulink> for details.
            Defaults to true.</para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>ForceDHCPv6PDOtherInformation=</varname></term>
          <listitem>
            <para>Takes a boolean that enforces DHCPv6 stateful mode when the 'Other information' bit is set in
            Router Advertisement messages. By default setting only the 'O' bit in Router Advertisements
            makes DHCPv6 request network information in a stateless manner using a two-message Information
            Request and Information Reply message exchange.
            <ulink url="https://tools.ietf.org/html/rfc7084">RFC 7084</ulink>, requirement WPD-4, updates
            this behavior for a Customer Edge router so that stateful DHCPv6 Prefix Delegation is also
            requested when only the 'O' bit is set in Router Advertisements. This option enables such a CE
            behavior as it is impossible to automatically distinguish the intention of the 'O' bit otherwise.
            By default this option is set to 'false', enable it if no prefixes are delegated when the device
            should be acting as a CE router.</para>
          </listitem>
        </varlistentry>

      </variablelist>
    </refsect1>

  <refsect1>
    <title>[IPv6AcceptRA] Section Options</title>
      <para>The <literal>[IPv6AcceptRA]</literal> section configures the IPv6 Router Advertisement
      (RA) client, if it is enabled with the <varname>IPv6AcceptRA=</varname> setting described
      above:</para>

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>UseDNS=</varname></term>
          <listitem>
            <para>When true (the default), the DNS servers received in the Router Advertisement will be used and take
            precedence over any statically configured ones.</para>

            <para>This corresponds to the <option>nameserver</option> option in <citerefentry
            project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>UseDomains=</varname></term>
          <listitem>
            <para>Takes a boolean, or the special value <literal>route</literal>. When true, the domain name
            received via IPv6 Router Advertisement (RA) will be used as DNS search domain over this link, similar to
            the effect of the <option>Domains=</option> setting. If set to <literal>route</literal>, the domain name
            received via IPv6 RA will be used for routing DNS queries only, but not for searching, similar to the
            effect of the <option>Domains=</option> setting when the argument is prefixed with
            <literal>~</literal>. Defaults to false.</para>

            <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
            of all host names, in particular of single-label names. It is generally safer to use the supplied domain
            only as routing domain, rather than as search domain, in order to not have it affect local resolution of
            single-label names.</para>

            <para>When set to true, this setting corresponds to the <option>domain</option> option in <citerefentry
            project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>RouteTable=<replaceable>num</replaceable></varname></term>
          <listitem>
            <para>The table identifier for the routes received in the Router Advertisement
            (a number between 1 and 4294967295, or 0 to unset).
            The table can be retrieved using <command>ip route show table <replaceable>num</replaceable></command>.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>UseAutonomousPrefix=</varname></term>
          <listitem>
            <para>When true (the default), the autonomous prefix received in the Router Advertisement will be used and take
            precedence over any statically configured ones.</para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><varname>UseOnLinkPrefix=</varname></term>
          <listitem>
            <para>When true (the default), the onlink prefix received in the Router Advertisement will be used and take
            precedence over any statically configured ones.</para>
          </listitem>
        </varlistentry>

      </variablelist>
  </refsect1>

  <refsect1>
    <title>[DHCPServer] Section Options</title>
    <para>The <literal>[DHCPServer]</literal> section contains
    settings for the DHCP server, if enabled via the
    <varname>DHCPServer=</varname> option described above:</para>

    <variablelist class='network-directives'>

      <varlistentry>
        <term><varname>PoolOffset=</varname></term>
        <term><varname>PoolSize=</varname></term>

        <listitem><para>Configures the pool of addresses to hand out. The pool
        is a contiguous sequence of IP addresses in the subnet configured for
        the server address, which does not include the subnet nor the broadcast
        address. <varname>PoolOffset=</varname> takes the offset of the pool
        from the start of subnet, or zero to use the default value.
        <varname>PoolSize=</varname> takes the number of IP addresses in the
        pool or zero to use the default value. By default, the pool starts at
        the first address after the subnet address and takes up the rest of
        the subnet, excluding the broadcast address. If the pool includes
        the server address (the default), this is reserved and not handed
        out to clients.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>DefaultLeaseTimeSec=</varname></term>
        <term><varname>MaxLeaseTimeSec=</varname></term>

        <listitem><para>Control the default and maximum DHCP lease
        time to pass to clients. These settings take time values in seconds or
        another common time unit, depending on the suffix. The default
        lease time is used for clients that did not ask for a specific
        lease time. If a client asks for a lease time longer than the
        maximum lease time, it is automatically shortened to the
        specified time. The default lease time defaults to 1h, the
        maximum lease time to 12h. Shorter lease times are beneficial
        if the configuration data in DHCP leases changes frequently
        and clients shall learn the new settings with shorter
        latencies. Longer lease times reduce the generated DHCP
        network traffic.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>EmitDNS=</varname></term>
        <term><varname>DNS=</varname></term>

        <listitem><para>Takes a boolean. Configures whether the DHCP leases handed out
        to clients shall contain DNS server information. Defaults to <literal>yes</literal>.
        The DNS servers to pass to clients may be configured with the
        <varname>DNS=</varname> option, which takes a list of IPv4
        addresses. If the <varname>EmitDNS=</varname> option is
        enabled but no servers configured, the servers are
        automatically propagated from an "uplink" interface that has
        appropriate servers set. The "uplink" interface is determined
        by the default route of the system with the highest
        priority. Note that this information is acquired at the time
        the lease is handed out, and does not take uplink interfaces
        into account that acquire DNS or NTP server information at a
        later point. DNS server propagation does not take
        <filename>/etc/resolv.conf</filename> into account. Also, note
        that the leases are not refreshed if the uplink network
        configuration changes. To ensure clients regularly acquire the
        most current uplink DNS server information, it is thus
        advisable to shorten the DHCP lease time via
        <varname>MaxLeaseTimeSec=</varname> described
        above.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>EmitNTP=</varname></term>
        <term><varname>NTP=</varname></term>

        <listitem><para>Similar to the <varname>EmitDNS=</varname> and
        <varname>DNS=</varname> settings described above, these
        settings configure whether and what NTP server information
        shall be emitted as part of the DHCP lease. The same syntax,
        propagation semantics and defaults apply as for
        <varname>EmitDNS=</varname> and
        <varname>DNS=</varname>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>EmitRouter=</varname></term>

        <listitem><para>Similar to the <varname>EmitDNS=</varname>
        setting described above, this setting configures whether the
        DHCP lease should contain the router option. The same syntax,
        propagation semantics and defaults apply as for
        <varname>EmitDNS=</varname>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>EmitTimezone=</varname></term>
        <term><varname>Timezone=</varname></term>

        <listitem><para>Takes a boolean. Configures whether the DHCP leases handed out
        to clients shall contain timezone information. Defaults to <literal>yes</literal>. The
        <varname>Timezone=</varname> setting takes a timezone string
        (such as <literal>Europe/Berlin</literal> or
        <literal>UTC</literal>) to pass to clients. If no explicit
        timezone is set, the system timezone of the local host is
        propagated, as determined by the
        <filename>/etc/localtime</filename> symlink.</para></listitem>
      </varlistentry>

    </variablelist>
  </refsect1>

  <refsect1>
    <title>[IPv6PrefixDelegation] Section Options</title>
    <para>The <literal>[IPv6PrefixDelegation]</literal> section contains
    settings for sending IPv6 Router Advertisements and whether to act as
    a router, if enabled via the <varname>IPv6PrefixDelegation=</varname>
    option described above. IPv6 network prefixes are defined with one or
    more <literal>[IPv6Prefix]</literal> sections.</para>

    <variablelist class='network-directives'>

      <varlistentry>
        <term><varname>Managed=</varname></term>
        <term><varname>OtherInformation=</varname></term>

        <listitem><para>Takes a boolean. Controls whether a DHCPv6 server is used to acquire IPv6
        addresses on the network link when <varname>Managed=</varname>
        is set to <literal>true</literal> or if only additional network
        information can be obtained via DHCPv6 for the network link when
        <varname>OtherInformation=</varname> is set to
        <literal>true</literal>. Both settings default to
        <literal>false</literal>, which means that a DHCPv6 server is not being
        used.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>RouterLifetimeSec=</varname></term>

        <listitem><para>Takes a timespan. Configures the IPv6 router lifetime in seconds. If set,
        this host also announces itself in Router Advertisements as an IPv6
        router for the network link. When unset, the host is not acting as a router.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>RouterPreference=</varname></term>

        <listitem><para>Configures IPv6 router preference if
        <varname>RouterLifetimeSec=</varname> is non-zero. Valid values are
        <literal>high</literal>, <literal>medium</literal> and
        <literal>low</literal>, with <literal>normal</literal> and
        <literal>default</literal> added as synonyms for
        <literal>medium</literal> just to make configuration easier. See
        <ulink url="https://tools.ietf.org/html/rfc4191">RFC 4191</ulink>
        for details. Defaults to <literal>medium</literal>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>EmitDNS=</varname></term>
        <term><varname>DNS=</varname></term>

        <listitem><para><varname>DNS=</varname> specifies a list of recursive
        DNS server IPv6 addresses that distributed via Router Advertisement
        messages when <varname>EmitDNS=</varname> is true. If <varname>DNS=
        </varname> is empty, DNS servers are read from the
        <literal>[Network]</literal> section. If the
        <literal>[Network]</literal> section does not contain any DNS servers
        either, DNS servers from the uplink with the highest priority default
        route are used. When <varname>EmitDNS=</varname> is false, no DNS server
        information is sent in Router Advertisement messages.
        <varname>EmitDNS=</varname> defaults to true.
        </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>EmitDomains=</varname></term>
        <term><varname>Domains=</varname></term>

        <listitem><para>A list of DNS search domains distributed via Router
        Advertisement messages when <varname>EmitDomains=</varname> is true. If
        <varname>Domains=</varname> is empty, DNS search domains are read from the
        <literal>[Network]</literal> section. If the <literal>[Network]</literal>
        section does not contain any DNS search domains either, DNS search
        domains from the uplink with the highest priority default route are
        used. When <varname>EmitDomains=</varname> is false, no DNS search domain
        information is sent in Router Advertisement messages.
        <varname>EmitDomains=</varname> defaults to true.
        </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>DNSLifetimeSec=</varname></term>

        <listitem><para>Lifetime in seconds for the DNS server addresses listed
        in <varname>DNS=</varname> and search domains listed in
        <varname>Domains=</varname>.</para></listitem>
      </varlistentry>

    </variablelist>
    </refsect1>

      <refsect1>
    <title>[IPv6Prefix] Section Options</title>
    <para>One or more <literal>[IPv6Prefix]</literal> sections contain the IPv6
    prefixes that are announced via Router Advertisements. See
    <ulink url="https://tools.ietf.org/html/rfc4861">RFC 4861</ulink>
    for further details.</para>

    <variablelist class='network-directives'>

      <varlistentry>
        <term><varname>AddressAutoconfiguration=</varname></term>
        <term><varname>OnLink=</varname></term>

        <listitem><para>Takes a boolean to specify whether IPv6 addresses can be
        autoconfigured with this prefix and whether the prefix can be used for
        onlink determination. Both settings default to <literal>true</literal>
        in order to ease configuration.
        </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>Prefix=</varname></term>

        <listitem><para>The IPv6 prefix that is to be distributed to hosts.
        Similarly to configuring static IPv6 addresses, the setting is
        configured as an IPv6 prefix and its prefix length, separated by a
        <literal>/</literal> character. Use multiple
        <literal>[IPv6Prefix]</literal> sections to configure multiple IPv6
        prefixes since prefix lifetimes, address autoconfiguration and onlink
        status may differ from one prefix to another.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>PreferredLifetimeSec=</varname></term>
        <term><varname>ValidLifetimeSec=</varname></term>

        <listitem><para>Preferred and valid lifetimes for the prefix measured in
        seconds. <varname>PreferredLifetimeSec=</varname> defaults to 604800
        seconds (one week) and <varname>ValidLifetimeSec=</varname> defaults
        to 2592000 seconds (30 days).</para></listitem>
      </varlistentry>

    </variablelist>
    </refsect1>

    <refsect1>
    <title>[Bridge] Section Options</title>
      <para>The <literal>[Bridge]</literal> section accepts the
      following keys.</para>
      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>UnicastFlood=</varname></term>
          <listitem>
            <para>Takes a boolean. Controls whether the bridge should flood
            traffic for which an FDB entry is missing and the destination
            is unknown through this port. When unset, the kernel's default will be used.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>MulticastFlood=</varname></term>
          <listitem>
            <para>Takes a boolean. Controls whether the bridge should flood
            traffic for which an MDB entry is missing and the destination
            is unknown through this port. When unset, the kernel's default will be used.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>MulticastToUnicast=</varname></term>
          <listitem>
            <para>Takes a boolean. Multicast to unicast works on top of the multicast snooping feature of
            the bridge. Which means unicast copies are only delivered to hosts which are interested in it.
            When unset, the kernel's default will be used.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>NeighborSuppression=</varname></term>
          <listitem>
            <para>Takes a boolean. Configures whether ARP and ND neighbor suppression is enabled for
            this port. When unset, the kernel's default will be used.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Learning=</varname></term>
          <listitem>
            <para>Takes a boolean. Configures whether MAC address learning is enabled for
            this port. When unset, the kernel's default will be used.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>HairPin=</varname></term>
          <listitem>
            <para>Takes a boolean. Configures whether traffic may be sent back
            out of the port on which it was received. When this flag is false, and the bridge
            will not forward traffic back out of the receiving port.
            When unset, the kernel's default will be used.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>UseBPDU=</varname></term>
          <listitem>
            <para>Takes a boolean. Configures whether STP Bridge Protocol Data Units will be
            processed by the bridge port. When unset, the kernel's default will be used.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>FastLeave=</varname></term>
          <listitem>
            <para>Takes a boolean. This flag allows the bridge to immediately stop multicast
            traffic on a port that receives an IGMP Leave message. It is only used with
            IGMP snooping if enabled on the bridge. When unset, the kernel's default will be used.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>AllowPortToBeRoot=</varname></term>
          <listitem>
            <para>Takes a boolean. Configures whether a given port is allowed to
            become a root port. Only used when STP is enabled on the bridge.
            When unset, the kernel's default will be used.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Cost=</varname></term>
          <listitem>
            <para>Sets the "cost" of sending packets of this interface.
            Each port in a bridge may have a different speed and the cost
            is used to decide which link to use. Faster interfaces
            should have lower costs. It is an integer value between 1 and
            65535.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Priority=</varname></term>
          <listitem>
            <para>Sets the "priority" of sending packets on this interface.
            Each port in a bridge may have a different priority which is used
            to decide which link to use. Lower value means higher priority.
            It is an integer value between 0 to 63. Networkd does not set any
            default, meaning the kernel default value of 32 is used.</para>
          </listitem>
        </varlistentry>
      </variablelist>
  </refsect1>
  <refsect1>
    <title>[BridgeFDB] Section Options</title>
      <para>The <literal>[BridgeFDB]</literal> section manages the
      forwarding database table of a port and accepts the following
      keys. Specify several <literal>[BridgeFDB]</literal> sections to
      configure several static MAC table entries.</para>

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>MACAddress=</varname></term>
          <listitem>
            <para>As in the <literal>[Network]</literal> section. This
            key is mandatory.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>VLANId=</varname></term>
          <listitem>
            <para>The VLAN ID for the new static MAC table entry. If
            omitted, no VLAN ID information is appended to the new static MAC
            table entry.</para>
          </listitem>
        </varlistentry>
      </variablelist>
  </refsect1>

  <refsect1>
    <title>[CAN] Section Options</title>
      <para>The <literal>[CAN]</literal> section manages the Controller Area Network (CAN bus) and accepts the
      following keys.</para>
      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>BitRate=</varname></term>
          <listitem>
            <para>The bitrate of CAN device in bits per second. The usual SI prefixes (K, M) with the base of 1000 can
            be used here.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>SamplePoint=</varname></term>
          <listitem>
            <para>Optional sample point in percent with one decimal (e.g. <literal>75%</literal>,
            <literal>87.5%</literal>) or permille (e.g. <literal>875‰</literal>).</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>RestartSec=</varname></term>
          <listitem>
            <para>Automatic restart delay time. If set to a non-zero value, a restart of the CAN controller will be
            triggered automatically in case of a bus-off condition after the specified delay time. Subsecond delays can
            be specified using decimals (e.g. <literal>0.1s</literal>) or a <literal>ms</literal> or
            <literal>us</literal> postfix. Using <literal>infinity</literal> or <literal>0</literal> will turn the
            automatic restart off. By default automatic restart is disabled.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>TripleSampling=</varname></term>
          <listitem>
            <para>Takes a boolean. When <literal>yes</literal>, three samples (instead of one) are used to determine
            the value of a received bit by majority rule. When unset, the kernel's default will be used.</para>
          </listitem>
        </varlistentry>
      </variablelist>
  </refsect1>

  <refsect1>
    <title>[BridgeVLAN] Section Options</title>
      <para>The <literal>[BridgeVLAN]</literal> section manages the VLAN ID configuration of a bridge port and accepts
      the following keys. Specify several <literal>[BridgeVLAN]</literal> sections to configure several VLAN entries.
      The <varname>VLANFiltering=</varname> option has to be enabled, see <literal>[Bridge]</literal> section in
      <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>VLAN=</varname></term>
          <listitem>
            <para>The VLAN ID allowed on the port. This can be either a single ID or a range M-N. VLAN IDs are valid
            from 1 to 4094.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>EgressUntagged=</varname></term>
          <listitem>
            <para>The VLAN ID specified here will be used to untag frames on egress. Configuring
            <varname>EgressUntagged=</varname> implicates the use of <varname>VLAN=</varname> above and will enable the
            VLAN ID for ingress as well. This can be either a single ID or a range M-N.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>PVID=</varname></term>
          <listitem>
            <para>The Port VLAN ID specified here is assigned to all untagged frames at ingress.
            <varname>PVID=</varname> can be used only once. Configuring <varname>PVID=</varname> implicates the use of
            <varname>VLAN=</varname> above and will enable the VLAN ID for ingress as well.</para>
          </listitem>
        </varlistentry>
      </variablelist>
  </refsect1>

  <refsect1>
    <title>Examples</title>
    <example>
      <title>Static network configuration</title>

      <programlisting># /etc/systemd/network/50-static.network
[Match]
Name=enp2s0

[Network]
Address=192.168.0.15/24
Gateway=192.168.0.1</programlisting>

      <para>This brings interface <literal>enp2s0</literal> up with a static address. The
      specified gateway will be used for a default route.</para>
    </example>

    <example>
      <title>DHCP on ethernet links</title>

      <programlisting># /etc/systemd/network/80-dhcp.network
[Match]
Name=en*

[Network]
DHCP=yes</programlisting>

      <para>This will enable DHCPv4 and DHCPv6 on all interfaces with names starting with
      <literal>en</literal> (i.e. ethernet interfaces).</para>
    </example>

    <example>
      <title>A bridge with two enslaved links</title>

      <programlisting># /etc/systemd/network/25-bridge-static.network
[Match]
Name=bridge0

[Network]
Address=192.168.0.15/24
Gateway=192.168.0.1
DNS=192.168.0.1</programlisting>

      <programlisting># /etc/systemd/network/25-bridge-slave-interface-1.network
[Match]
Name=enp2s0

[Network]
Bridge=bridge0</programlisting>

      <programlisting># /etc/systemd/network/25-bridge-slave-interface-2.network
[Match]
Name=wlp3s0

[Network]
Bridge=bridge0</programlisting>

      <para>This creates a bridge and attaches devices <literal>enp2s0</literal> and
      <literal>wlp3s0</literal> to it. The bridge will have the specified static address
      and network assigned, and a default route via the specified gateway will be
      added. The specified DNS server will be added to the global list of DNS resolvers.
      </para>
    </example>

    <example>
      <title></title>

      <programlisting>
# /etc/systemd/network/20-bridge-slave-interface-vlan.network
[Match]
Name=enp2s0

[Network]
Bridge=bridge0

[BridgeVLAN]
VLAN=1-32
PVID=42
EgressUntagged=42

[BridgeVLAN]
VLAN=100-200

[BridgeVLAN]
EgressUntagged=300-400</programlisting>

    <para>This overrides the configuration specified in the previous example for the
    interface <literal>enp2s0</literal>, and enables VLAN on that bridge port. VLAN IDs
    1-32, 42, 100-400 will be allowed. Packets tagged with VLAN IDs 42, 300-400 will be
    untagged when they leave on this interface. Untagged packets which arrive on this
    interface will be assigned VLAN ID 42.</para>
    </example>

    <example>
      <title>Various tunnels</title>

      <programlisting>/etc/systemd/network/25-tunnels.network
[Match]
Name=ens1

[Network]
Tunnel=ipip-tun
Tunnel=sit-tun
Tunnel=gre-tun
Tunnel=vti-tun
      </programlisting>

      <programlisting>/etc/systemd/network/25-tunnel-ipip.netdev
[NetDev]
Name=ipip-tun
Kind=ipip
      </programlisting>

      <programlisting>/etc/systemd/network/25-tunnel-sit.netdev
[NetDev]
Name=sit-tun
Kind=sit
      </programlisting>

      <programlisting>/etc/systemd/network/25-tunnel-gre.netdev
[NetDev]
Name=gre-tun
Kind=gre
      </programlisting>

      <programlisting>/etc/systemd/network/25-tunnel-vti.netdev
[NetDev]
Name=vti-tun
Kind=vti
      </programlisting>

      <para>This will bring interface <literal>ens1</literal> up and create an IPIP tunnel,
      a SIT tunnel, a GRE tunnel, and a VTI tunnel using it.</para>
    </example>

    <example>
      <title>A bond device</title>

      <programlisting># /etc/systemd/network/30-bond1.network
[Match]
Name=bond1

[Network]
DHCP=ipv6
</programlisting>

      <programlisting># /etc/systemd/network/30-bond1.netdev
[NetDev]
Name=bond1
Kind=bond
</programlisting>

      <programlisting># /etc/systemd/network/30-bond1-dev1.network
[Match]
MACAddress=52:54:00:e9:64:41

[Network]
Bond=bond1
</programlisting>

      <programlisting># /etc/systemd/network/30-bond1-dev2.network
[Match]
MACAddress=52:54:00:e9:64:42

[Network]
Bond=bond1
</programlisting>

    <para>This will create a bond device <literal>bond1</literal> and enslave the two
    devices with MAC addresses 52:54:00:e9:64:41 and 52:54:00:e9:64:42 to it. IPv6 DHCP
    will be used to acquire an address.</para>
    </example>

    <example>
      <title>Virtual Routing and Forwarding (VRF)</title>
      <para>Add the <literal>bond1</literal> interface to the VRF master interface
      <literal>vrf1</literal>. This will redirect routes generated on this interface to be
      within the routing table defined during VRF creation. For kernels before 4.8 traffic
      won't be redirected towards the VRFs routing table unless specific ip-rules are added.
      </para>
      <programlisting># /etc/systemd/network/25-vrf.network
[Match]
Name=bond1

[Network]
VRF=vrf1
</programlisting>
    </example>

    <example>
      <title>MacVTap</title>
      <para>This brings up a network interface <literal>macvtap-test</literal>
      and attaches it to <literal>enp0s25</literal>.</para>
      <programlisting># /usr/lib/systemd/network/25-macvtap.network
[Match]
Name=enp0s25

[Network]
MACVTAP=macvtap-test
</programlisting>
    </example>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
    </para>
  </refsect1>

</refentry>