networkd.conf, networkd.conf.d — Global Network configuration files
/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 |
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.
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.
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.
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:numberdefault", "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.
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
for more details about the sysctl options. Defaults to unset and the sysctl options will not be
changed.
If an interface is configured with a .network file that enables IPMasquerade=
for IPv4 (that is, "ipv4" or "both"), this setting is implied
unless explicitly specified. See IPMasquerade= in
systemd.network(5)
for more details.
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
for more details about the sysctl options. Defaults to unset and the sysctl options will not be
changed.
If an interface is configured with a .network file that enables IPMasquerade=
for IPv6 (that is, "ipv6" or "both"), this setting is implied
unless explicitly specified. See IPMasquerade= in
systemd.network(5)
for more details.
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".
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".
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.
An [IPv6AddressLabel] section accepts the following keys. Specify multiple [IPv6AddressLabel] sections to configure multiple address labels. IPv6 address labels are used for address selection. See RFC 3484. Precedence is managed by userspace, and only the label itself is stored in the kernel.
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 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.
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, RFC 6355. 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".
UseDomains=¶Same as the one in the [IPv6AcceptRA] section, but applied for DHCPv4 protocol.
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:
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.
systemd(1), systemd.network(5), systemd-networkd.service(8), machine-id(5), sd_id128_get_machine_app_specific(3)
[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.