Provided by: systemd_245.4-4ubuntu3_amd64 bug


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






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


       The default configuration is defined during compilation, so a configuration file is only
       needed when it is necessary to deviate from those defaults. By default, the configuration
       file in /etc/systemd/ contains commented out entries showing the defaults as a guide to
       the administrator. This file can be edited to create local overrides.

       When packages need to customize the configuration, they can install configuration snippets
       in /usr/lib/systemd/*.conf.d/ or /usr/local/lib/systemd/*.conf.d/. The main configuration
       file is read before any of the configuration directories, and has the lowest precedence;
       entries in a file in any configuration directory override entries in the single
       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 with the lexicographically latest name takes
       precedence. For options which accept a list of values, entries are collected as they occur
       in files sorted lexicographically.

       Files in /etc/ are reserved for the local administrator, who may use this logic to
       override the configuration files installed by vendor packages. 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.


       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 sd_id128_get_machine_app_specific(3).

           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".


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


        1. RFC 3315

        2. RFC 3315

        3. RFC 6355