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networkd.conf(5)


NAME

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

SYNOPSIS

   /etc/systemd/networkd.conf

   /etc/systemd/networkd.conf.d/*.conf

   /lib/systemd/networkd.conf.d/*.conf

DESCRIPTION

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

CONFIGURATION DIRECTORIES AND PRECEDENCE

   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/. Files in /etc/
   are reserved for the local administrator, who may use this logic to
   override the configuration files installed by vendor packages. 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 which of the subdirectories they
   reside in. If multiple files specify the same option, the entry in the
   file with the lexicographically latest name takes 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.

[DHCP] SECTION OPTIONS

   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 systemd.network(5).

   The following options are understood:

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

       The following values are understood:

       vendor
           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.

       link-layer-time, link-layer, uuid
           Those values are parsed and can be used to set the DUID type
           field, but DUID contents must be provided using DUIDRawData=.

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

   DUIDRawData=
       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 generates using the machine-id from the
       /etc/machine-id file. To configure DUID per-network, see
       systemd.network(5). The configured DHCP DUID should conform to the
       specification in RFC 3315[2], RFC 6355[3]. To configure IAID, see
       systemd.network(5).

       Example 1. A DUIDType=vendor with a custom value

           DUIDType=vendor
           DUIDRawData=00:00:ab:11:f9:2a:c2:77:29:f9:5c:00

       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

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

NOTES

    1. RFC 3315
       https://tools.ietf.org/html/rfc3315#section-9

    2. RFC 3315
       http://tools.ietf.org/html/rfc3315#section-9

    3. RFC 6355
       http://tools.ietf.org/html/rfc6355



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