networkd.conf(5) — Linux manual page


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

NAME         top

       networkd.conf, networkd.conf.d - Global Network configuration

SYNOPSIS         top




DESCRIPTION         top

       These configuration files control global network parameters.
       Currently the DHCP Unique Identifier (DUID).


       The default configuration is set during compilation, so
       configuration is only needed when it is necessary to deviate from
       those defaults. Initially, the main configuration file in
       /etc/systemd/ contains commented out entries showing the defaults
       as a guide to the administrator. Local overrides can be created
       by editing this file or by creating drop-ins, as described below.
       Using drop-ins for local configuration is recommended over
       modifications to the main configuration file.

       In addition to the "main" configuration file, drop-in
       configuration snippets are read from /usr/lib/systemd/*.conf.d/,
       /usr/local/lib/systemd/*.conf.d/, and /etc/systemd/*.conf.d/.
       Those drop-ins have higher precedence and override the main
       configuration file. Files in the *.conf.d/ configuration
       subdirectories are sorted by their filename in lexicographic
       order, regardless of in which of the subdirectories they reside.
       When multiple files specify the same option, for options which
       accept just a single value, the entry in the file sorted last
       takes precedence, and for options which accept a list of values,
       entries are collected as they occur in the sorted files.

       When packages need to customize the configuration, they can
       install drop-ins under /usr/. Files in /etc/ are reserved for the
       local administrator, who may use this logic to override the
       configuration files installed by vendor packages. Drop-ins have
       to be used to override package drop-ins, since the main
       configuration file has lower precedence. It is recommended to
       prefix all filenames in those subdirectories with a two-digit
       number and a dash, to simplify the ordering of the files.

       To disable a configuration file supplied by the vendor, the
       recommended way is to place a symlink to /dev/null in the
       configuration directory in /etc/, with the same filename as the
       vendor configuration file.


       The following options are available in the [Network] section:

           Takes a boolean. If set to yes, then systemd-networkd
           measures the traffic of each interface, and networkctl status
           INTERFACE shows the measured speed. Defaults to no.

           Specifies the time interval to calculate the traffic speed of
           each interface. If SpeedMeter=no, the value is ignored.
           Defaults to 10sec.

           A boolean. When true, systemd-networkd will store any routes
           configured by other tools in its memory. When false,
           systemd-networkd will not manage the foreign routes, thus
           they are kept even if KeepConfiguration= is false. Defaults
           to yes.

           Defines the route table name. Takes a whitespace-separated
           list of the pairs of route table name and number. The route
           table name and number in each pair are separated with a
           colon, i.e., "name:number". The route table name must not be
           "default", "main", or "local", as these route table names are
           predefined with route table number 253, 254, and 255,
           respectively. The route table number must be an integer in
           the range 1...4294967295. This setting can be specified
           multiple times. If an empty string is specified, then the
           list specified earlier are cleared. Defaults to unset.


       This section configures the DHCP Unique Identifier (DUID) value
       used by DHCP protocol. DHCPv6 client protocol sends the DHCP
       Unique Identifier and the interface Identity Association
       Identifier (IAID) to a DHCP server when acquiring a dynamic IPv6
       address. DHCPv4 client protocol sends IAID and DUID to the DHCP
       server when acquiring a dynamic IPv4 address if
       ClientIdentifier=duid. IAID and DUID allows a DHCP server to
       uniquely identify the machine and the interface requesting a DHCP
       IP. To configure IAID and ClientIdentifier, see

       The following options are understood:

           Specifies how the DUID should be generated. See RFC 3315[1]
           for a description of all the options.

           The following values are understood:

               If "DUIDType=vendor", then the DUID value will be
               generated using "43793" as the vendor identifier
               (systemd) and hashed contents of machine-id(5). This is
               the default if DUIDType= is not specified.

               If "DUIDType=uuid", and DUIDRawData= is not set, then the
               product UUID is used as a DUID value. If a system does
               not have valid product UUID, then an application-specific
               machine-id(5) is used as a DUID value. About the
               application-specific machine ID, see

           link-layer-time[:TIME], link-layer
               If "link-layer-time" or "link-layer" is specified, then
               the MAC address of the interface is used as a DUID value.
               The value "link-layer-time" can take additional time
               value after a colon, e.g.  "link-layer-time:2018-01-23
               12:34:56 UTC". The default time value is "2000-01-01
               00:00:00 UTC".

           In all cases, DUIDRawData= can be used to override the actual
           DUID value that is used.

           Specifies the DHCP DUID value as a single newline-terminated,
           hexadecimal string, with each byte separated by ":". The DUID
           that is sent is composed of the DUID type specified by
           DUIDType= and the value configured here.

           The DUID value specified here overrides the DUID that
           systemd-networkd.service(8) generates from the machine ID. To
           configure DUID per-network, see The
           configured DHCP DUID should conform to the specification in
           RFC 3315[2], RFC 6355[3]. To configure IAID, see

           Example 1. A DUIDType=vendor with a custom value


           This specifies a 14 byte DUID, with the type DUID-EN
           ("00:02"), enterprise number 43793 ("00:00:ab:11"), and
           identifier value "f9:2a:c2:77:29:f9:5c:00".

SEE ALSO         top

       systemd(1),, systemd-networkd.service(8),
       machine-id(5), sd_id128_get_machine_app_specific(3)

NOTES         top

        1. RFC 3315

        2. RFC 3315

        3. RFC 6355

COLOPHON         top

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systemd 248                                             NETWORKD.CONF(5)

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