Ubuntu Manpage: networkd.conf, networkd.conf.d - Global Network configuration files

Provided by: systemd_256.5-2ubuntu3.1_amd64

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.

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

NAME

SYNOPSIS

DESCRIPTION

CONFIGURATION DIRECTORIES AND PRECEDENCE

[NETWORK] SECTION OPTIONS

[IPV6ACCEPTRA] SECTION OPTIONS

[DHCPV4] SECTION OPTIONS

[DHCPV6] SECTION OPTIONS

[DHCPSERVER] SECTION OPTIONS

SEE ALSO

NOTES