networkd.conf(5) — Linux manual page
NETWORKD.CONF(5) networkd.conf NETWORKD.CONF(5)
NAME
networkd.conf, networkd.conf.d - Global Network configuration
files
SYNOPSIS
/etc/systemd/networkd.conf
/run/systemd/networkd.conf
/usr/local/lib/systemd/networkd.conf
/usr/lib/systemd/networkd.conf
/etc/systemd/networkd.conf.d/*.conf
/run/systemd/networkd.conf.d/*.conf
/usr/local/lib/systemd/networkd.conf.d/*.conf
/usr/lib/systemd/networkd.conf.d/*.conf
DESCRIPTION
These configuration files control global network parameters.
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. The main configuration file is loaded from one of
the listed directories in order of priority, only the first file
found is used: /etc/systemd/, /run/systemd/,
/usr/local/lib/systemd/ [1], /usr/lib/systemd/. The vendor
version of the file contains commented out entries showing the
defaults as a guide to the administrator. Local overrides can
also be created by creating drop-ins, as described below. The
main configuration file can also be edited for this purpose (or a
copy in /etc/ if it's shipped under /usr/), however 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. This also defines a
concept of drop-in priorities to allow OS vendors to ship
drop-ins within a specific range lower than the range used by
users. This should lower the risk of package drop-ins overriding
accidentally drop-ins defined by users. It is recommended to use
the range 10-40 for drop-ins in /usr/ and the range 60-90 for
drop-ins in /etc/ and /run/, to make sure that local and
transient drop-ins take priority over drop-ins shipped by the OS
vendor.
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.
Added in version 244.
SpeedMeterIntervalSec=
Specifies the time interval to calculate the traffic speed of
each interface. If SpeedMeter=no, the value is ignored.
Defaults to 10sec.
Added in version 244.
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.
Added in version 249.
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.
Added in version 246.
ManageForeignNextHops=
A boolean. When true, systemd-networkd will remove nexthops
that are not configured in .network files (except for routes
with protocol "kernel"). When false, it will not remove any
foreign nexthops, keeping them even if they are not
configured in a .network file. Defaults to yes.
Added in version 256.
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, except for predefined numbers 253,
254, and 255. This setting can be specified multiple times.
If an empty string is specified, then the list specified
earlier are cleared. Defaults to unset.
Added in version 248.
IPv4Forwarding=
Configures IPv4 packet forwarding for the system. Takes a
boolean value. This controls the
net.ipv4.conf.default.forwarding and
net.ipv4.conf.all.forwardingsysctl options. See IP Sysctl[2]
for more details about the sysctl options. Defaults to unset
and the sysctl options will not be changed.
Added in version 256.
IPv6Forwarding=
Configures IPv6 packet forwarding for the system. Takes a
boolean value. This controls the
net.ipv6.conf.default.forwarding and
net.ipv6.conf.all.forwarding sysctl options. See IP Sysctl[2]
for more details about the sysctl options. Defaults to unset
and the sysctl options will not be changed.
Added in version 256.
IPv6PrivacyExtensions=
Specifies the default value for per-network
IPv6PrivacyExtensions=. Takes a boolean or the special values
"prefer-public" and "kernel". See for details in
systemd.network(5). Defaults to "no".
Added in version 254.
UseDomains=
Specifies the network- and protocol-independent default value
for the same settings in [IPv6AcceptRA], [DHCPv4], and
[DHCPv6] sections below. Takes a boolean, or the special
value route. See the same setting in systemd.network(5).
Defaults to "no".
Added in version 256.
[IPV6ACCEPTRA] SECTION OPTIONS
This section configures the default setting of the Neighbor
Discovery. The following options are available in the
[IPv6AcceptRA] section:
UseDomains=
Specifies the network-independent default value for the same
setting in the [IPv6AcceptRA] section in systemd.network(5).
Takes a boolean, or the special value route. When
unspecified, the value specified in the [Network] section in
networkd.conf(5), which defaults to "no", will be used.
Added in version 256.
[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[3]
for a description of all the options.
This takes an integer in the range 0...65535, or one of the
following string values:
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.
Added in version 230.
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).
Added in version 230.
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".
Added in version 240.
In all cases, DUIDRawData= can be used to override the actual
DUID value that is used.
Added in version 230.
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[4], RFC 6355[5]. 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".
Added in version 230.
UseDomains=
Same as the one in the [IPv6AcceptRA] section, but applied
for DHCPv4 protocol.
Added in version 256.
[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.
Added in version 249.
UseDomains=
As in the [DHCPv4] section.
Added in version 256.
[DHCPSERVER] SECTION OPTIONS
This section configures the default setting of the DHCP server.
The following options are available in the [DHCPServer] section:
UseDomains=
Same as the one in the [IPv6AcceptRA] section, but applied
for DHCPv4 protocol.
Added in version 256.
SEE ALSO
systemd(1), systemd.network(5), systemd-networkd.service(8),
machine-id(5), sd_id128_get_machine_app_specific(3)
NOTES
1. 💣💥🧨💥💥💣 Please note that those configuration files must
be available at all times. If /usr/local/ is a separate
partition, it may not be available during early boot, and
must not be used for configuration.
2. IP Sysctl
https://docs.kernel.org/networking/ip-sysctl.html
3. RFC 3315
https://tools.ietf.org/html/rfc3315#section-9
4. RFC 3315
http://tools.ietf.org/html/rfc3315#section-9
5. RFC 6355
http://tools.ietf.org/html/rfc6355
COLOPHON
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systemd 257~devel NETWORKD.CONF(5)
Pages that refer to this page: networkctl(1), networkd.conf(5), systemd.netdev(5), systemd.network(5), systemd.directives(7), systemd.index(7), systemd.system-credentials(7), systemd-network-generator.service(8)