1NETWORKD.CONF(5)                 networkd.conf                NETWORKD.CONF(5)
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NAME

6       networkd.conf, networkd.conf.d - Global Network configuration files
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SYNOPSIS

9       /etc/systemd/networkd.conf
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11       /etc/systemd/networkd.conf.d/*.conf
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13       /usr/lib/systemd/networkd.conf.d/*.conf
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DESCRIPTION

16       These configuration files control global network parameters. Currently
17       the DHCP Unique Identifier (DUID).
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CONFIGURATION DIRECTORIES AND PRECEDENCE

20       The default configuration is defined during compilation, so a
21       configuration file is only needed when it is necessary to deviate from
22       those defaults. By default, the configuration file in /etc/systemd/
23       contains commented out entries showing the defaults as a guide to the
24       administrator. This file can be edited to create local overrides.
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26       When packages need to customize the configuration, they can install
27       configuration snippets in /usr/lib/systemd/*.conf.d/. Files in /etc/
28       are reserved for the local administrator, who may use this logic to
29       override the configuration files installed by vendor packages. The main
30       configuration file is read before any of the configuration directories,
31       and has the lowest precedence; entries in a file in any configuration
32       directory override entries in the single configuration file. Files in
33       the *.conf.d/ configuration subdirectories are sorted by their filename
34       in lexicographic order, regardless of which of the subdirectories they
35       reside in. When multiple files specify the same option, for options
36       which accept just a single value, the entry in the file with the
37       lexicographically latest name takes precedence. For options which
38       accept a list of values, entries are collected as they occur in files
39       sorted lexicographically. It is recommended to prefix all filenames in
40       those subdirectories with a two-digit number and a dash, to simplify
41       the ordering of the files.
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43       To disable a configuration file supplied by the vendor, the recommended
44       way is to place a symlink to /dev/null in the configuration directory
45       in /etc/, with the same filename as the vendor configuration file.
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[DHCP] SECTION OPTIONS

48       This section configures the DHCP Unique Identifier (DUID) value used by
49       DHCP protocol. DHCPv6 client protocol sends the DHCP Unique Identifier
50       and the interface Identity Association Identifier (IAID) to a DHCP
51       server when acquiring a dynamic IPv6 address. DHCPv4 client protocol
52       sends IAID and DUID to the DHCP server when acquiring a dynamic IPv4
53       address if ClientIdentifier=duid. IAID and DUID allows a DHCP server to
54       uniquely identify the machine and the interface requesting a DHCP IP.
55       To configure IAID and ClientIdentifier, see systemd.network(5).
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57       The following options are understood:
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59       DUIDType=
60           Specifies how the DUID should be generated. See RFC 3315[1] for a
61           description of all the options.
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63           The following values are understood:
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65           vendor
66               If "DUIDType=vendor", then the DUID value will be generated
67               using "43793" as the vendor identifier (systemd) and hashed
68               contents of machine-id(5). This is the default if DUIDType= is
69               not specified.
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71           link-layer-time, link-layer, uuid
72               Those values are parsed and can be used to set the DUID type
73               field, but DUID contents must be provided using DUIDRawData=.
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75           In all cases, DUIDRawData= can be used to override the actual DUID
76           value that is used.
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78       DUIDRawData=
79           Specifies the DHCP DUID value as a single newline-terminated,
80           hexadecimal string, with each byte separated by ":". The DUID that
81           is sent is composed of the DUID type specified by DUIDType= and the
82           value configured here.
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84           The DUID value specified here overrides the DUID that
85           systemd-networkd generates using the machine-id from the
86           /etc/machine-id file. To configure DUID per-network, see
87           systemd.network(5). The configured DHCP DUID should conform to the
88           specification in RFC 3315[2], RFC 6355[3]. To configure IAID, see
89           systemd.network(5).
90
91           Example 1. A DUIDType=vendor with a custom value
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93               DUIDType=vendor
94               DUIDRawData=00:00:ab:11:f9:2a:c2:77:29:f9:5c:00
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96           This specifies a 14 byte DUID, with the type DUID-EN ("00:02"),
97           enterprise number 43793 ("00:00:ab:11"), and identifier value
98           "f9:2a:c2:77:29:f9:5c:00".
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SEE ALSO

101       systemd(1), systemd.network(5), machine-id(1)
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NOTES

104        1. RFC 3315
105           https://tools.ietf.org/html/rfc3315#section-9
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107        2. RFC 3315
108           http://tools.ietf.org/html/rfc3315#section-9
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110        3. RFC 6355
111           http://tools.ietf.org/html/rfc6355
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115systemd 239                                                   NETWORKD.CONF(5)