networkd.conf(5) — Linux manual page

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 | COLOPHON

NETWORKD.CONF(5)              networkd.conf             NETWORKD.CONF(5)

NAME         top

       networkd.conf, networkd.conf.d - Global Network configuration
       files

SYNOPSIS         top

           /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         top

       These configuration files control global network parameters.

CONFIGURATION DIRECTORIES AND PRECEDENCE         top

       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         top

       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         top

       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         top

       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         top

       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         top

       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         top

       systemd(1), systemd.network(5), systemd-networkd.service(8),
       machine-id(5), sd_id128_get_machine_app_specific(3)

NOTES         top

        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         top

       This page is part of the systemd (systemd system and service
       manager) project.  Information about the project can be found at
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have
       a bug report for this manual page, see
       ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
       This page was obtained from the project's upstream Git repository
       ⟨https://github.com/systemd/systemd.git⟩ on 2024-06-14.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2024-06-13.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

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)