NETWORKD.CONF(5) networkd.conf 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 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.
[NETWORK] SECTION OPTIONS
The following options are available in the [Network] section:
SpeedMeter=
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.
SpeedMeterIntervalSec=
Specifies the time interval to calculate the traffic speed of each
interface. If SpeedMeter=no, the value is ignored. Defaults to
10sec.
ManageForeignRoutingPolicyRules=
A boolean. When true, systemd-networkd will remove rules that are
not configured in .network files (except for rules with protocol
"kernel"). When false, it will not remove any foreign rules,
keeping them even if they are not configured in a .network file.
Defaults to yes.
ManageForeignRoutes=
A boolean. When true, systemd-networkd will remove routes that are
not configured in .network files (except for routes with protocol
"kernel", "dhcp" when KeepConfiguration= is true or "dhcp", and
"static" when KeepConfiguration= is true or "static"). When false,
it will not remove any foreign routes, keeping them even if they
are not configured in a .network file. Defaults to yes.
RouteTable=
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.
[DHCPV4] SECTION OPTIONS
This section configures the DHCP Unique Identifier (DUID) value used by
DHCP protocol. 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 address. 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.
uuid
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.
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.service(8) generates from the machine ID. 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".
[DHCPV6] SECTION OPTIONS
This section configures the DHCP Unique Identifier (DUID) value used by
DHCPv6 protocol. DHCPv6 client protocol sends the DHCP Unique
Identifier and the interface Identity Association Identifier (IAID) to
a DHCPv6 server when acquiring a dynamic IPv6 address. IAID and DUID
allows a DHCPv6 server to uniquely identify the machine and the
interface requesting a DHCP IP address. To configure IAID, see
systemd.network(5).
The following options are understood:
DUIDType=, DUIDRawData=
As in the [DHCPv4] section.
SEE ALSO
systemd(1), systemd.network(5), systemd-networkd.service(8), machine-
id(5), sd_id128_get_machine_app_specific(3)
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
systemd 252 NETWORKD.CONF(5)
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