NAME
networkd.conf, networkd.conf.d - Global Network configuration files
SYNOPSIS
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 is 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=
Added in version 244.
SpeedMeterIntervalSec=
Added in version 244.
ManageForeignRoutingPolicyRules=
Added in version 249.
ManageForeignRoutes=
Added in version 246.
ManageForeignNextHops=
Added in version 256.
RouteTable=
Added in version 248.
IPv4Forwarding=
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.
Added in version 256.
IPv6Forwarding=
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.
Added in version 256.
IPv6PrivacyExtensions=
Added in version 254.
UseDomains=
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=
Added in version 256.
[IPV6ADDRESSLABEL] SECTION OPTIONS
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[3]. Precedence is managed by userspace, and only the label itself is stored in the kernel.
Label=
Added in version 257.
Prefix=
Added in version 257.
[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=
This takes an integer in the range 0...65535, or one of the following string values:
vendor
Added in version 230.
uuid
Added in version 230.
link-layer-time[:TIME], link-layer
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=
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[5], RFC 6355[6]. 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:00This 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=
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=
Added in version 249.
UseDomains=
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:
PersistLeases=
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
- 3.
RFC 3484
- 4.
RFC 3315
- 5.
RFC 3315
- 6.
RFC 6355