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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 249 NETWORKD.CONF(5)
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