SYSTEMD.LINK(5) systemd.link SYSTEMD.LINK(5)
NAME
systemd.link - Network device configuration
SYNOPSIS
link.link
DESCRIPTION
A plain ini-style text file that encodes configuration for matching
network devices, used by systemd-udevd(8) and in particular its
net_setup_link builtin. See systemd.syntax(7) for a general description
of the syntax.
The .link files are read from the files located in the system network
directory /lib/systemd/network and /usr/local/lib/systemd/network, the
volatile runtime network directory /run/systemd/network, and the local
administration network directory /etc/systemd/network. All
configuration files are collectively sorted and processed in
alphanumeric order, regardless of the directories in which they live.
However, files with identical filenames replace each other. It is
recommended that each filename is prefixed with a number (e.g.
10-eth0.link). Otherwise, the default .link files or those generated by
systemd-network-generator.service(8) may take precedence over user
configured files. Files in /etc/ have the highest priority, files in
/run/ take precedence over files with the same name in /lib/. This can
be used to override a system-supplied link file with a local file if
needed. As a special case, an empty file (file size 0) or symlink with
the same name pointing to /dev/null disables the configuration file
entirely (it is "masked").
Along with the link file foo.link, a "drop-in" directory foo.link.d/
may exist. All files with the suffix ".conf" from this directory will
be merged in the alphanumeric order and parsed after the main file
itself has been parsed. This is useful to alter or add configuration
settings, without having to modify the main configuration file. Each
drop-in file must have appropriate section headers.
In addition to /etc/systemd/network, drop-in ".d" directories can be
placed in /lib/systemd/network or /run/systemd/network directories.
Drop-in files in /etc/ take precedence over those in /run/ which in
turn take precedence over those in /lib/. Drop-in files under any of
these directories take precedence over the main link file wherever
located.
The link file contains a [Match] section, which determines if a given
link file may be applied to a given device, as well as a [Link] section
specifying how the device should be configured. The first (in lexical
order) of the link files that matches a given device is applied. Note
that a default file 99-default.link is shipped by the system. Any
user-supplied .link should hence have a lexically earlier name to be
considered at all.
See udevadm(8) for diagnosing problems with .link files.
[MATCH] SECTION OPTIONS
A link file is said to match an interface if all matches specified by
the [Match] section are satisfied. When a link file does not contain
valid settings in [Match] section, then the file will match all
interfaces and systemd-udevd warns about that. Hint: to avoid the
warning and to make it clear that all interfaces shall be matched, add
the following:
OriginalName=*
The first (in alphanumeric order) of the link files that matches a
given interface is applied, all later files are ignored, even if they
match as well. The following keys are accepted:
MACAddress=
A whitespace-separated list of hardware addresses. The acceptable
formats are:
colon-delimited hexadecimal
Each field must be one byte. E.g. "12:34:56:78:90:ab" or
"AA:BB:CC:DD:EE:FF".
hyphen-delimited hexadecimal
Each field must be one byte. E.g. "12-34-56-78-90-ab" or
"AA-BB-CC-DD-EE-FF".
dot-delimited hexadecimal
Each field must be two bytes. E.g. "1234.5678.90ab" or
"AABB.CCDD.EEFF".
IPv4 address format
E.g. "127.0.0.1" or "192.168.0.1".
IPv6 address format
E.g. "2001:0db8:85a3::8a2e:0370:7334" or "::1".
The total length of each MAC address must be 4 (for IPv4 tunnel), 6
(for Ethernet), 16 (for IPv6 tunnel), or 20 (for InfiniBand). This
option may appear more than once, in which case the lists are
merged. If the empty string is assigned to this option, the list of
hardware addresses defined prior to this is reset. Defaults to
unset.
PermanentMACAddress=
A whitespace-separated list of hardware's permanent addresses.
While MACAddress= matches the device's current MAC address, this
matches the device's permanent MAC address, which may be different
from the current one. Use full colon-, hyphen- or dot-delimited
hexadecimal, or IPv4 or IPv6 address format. This option may appear
more than once, in which case the lists are merged. If the empty
string is assigned to this option, the list of hardware addresses
defined prior to this is reset. Defaults to unset.
Path=
A whitespace-separated list of shell-style globs matching the
persistent path, as exposed by the udev property ID_PATH.
Driver=
A whitespace-separated list of shell-style globs matching the
driver currently bound to the device, as exposed by the udev
property ID_NET_DRIVER of its parent device, or if that is not set,
the driver as exposed by ethtool -i of the device itself. If the
list is prefixed with a "!", the test is inverted.
Type=
A whitespace-separated list of shell-style globs matching the
device type, as exposed by networkctl list. If the list is prefixed
with a "!", the test is inverted. Some valid values are "ether",
"loopback", "wlan", "wwan". Valid types are named either from the
udev "DEVTYPE" attribute, or "ARPHRD_" macros in linux/if_arp.h, so
this is not comprehensive.
Kind=
A whitespace-separated list of shell-style globs matching the
device kind, as exposed by networkctl status INTERFACE or ip -d
link show INTERFACE. If the list is prefixed with a "!", the test
is inverted. Some valid values are "bond", "bridge", "gre", "tun",
"veth". Valid kinds are given by netlink's "IFLA_INFO_KIND"
attribute, so this is not comprehensive.
Property=
A whitespace-separated list of udev property names with their
values after equals sign ("="). If multiple properties are
specified, the test results are ANDed. If the list is prefixed with
a "!", the test is inverted. If a value contains white spaces, then
please quote whole key and value pair. If a value contains
quotation, then please escape the quotation with "\".
Example: if a .link file has the following:
Property=ID_MODEL_ID=9999 "ID_VENDOR_FROM_DATABASE=vendor name" "KEY=with \"quotation\""
then, the .link file matches only when an interface has all the
above three properties.
OriginalName=
A whitespace-separated list of shell-style globs matching the
device name, as exposed by the udev property "INTERFACE". This
cannot be used to match on names that have already been changed
from userspace. Caution is advised when matching on kernel-assigned
names, as they are known to be unstable between reboots.
Host=
Matches against the hostname or machine ID of the host. See
ConditionHost= in systemd.unit(5) for details. When prefixed with
an exclamation mark ("!"), the result is negated. If an empty
string is assigned, the previously assigned value is cleared.
Virtualization=
Checks whether the system is executed in a virtualized environment
and optionally test whether it is a specific implementation. See
ConditionVirtualization= in systemd.unit(5) for details. When
prefixed with an exclamation mark ("!"), the result is negated. If
an empty string is assigned, the previously assigned value is
cleared.
KernelCommandLine=
Checks whether a specific kernel command line option is set. See
ConditionKernelCommandLine= in systemd.unit(5) for details. When
prefixed with an exclamation mark ("!"), the result is negated. If
an empty string is assigned, the previously assigned value is
cleared.
KernelVersion=
Checks whether the kernel version (as reported by uname -r) matches
a certain expression. See ConditionKernelVersion= in
systemd.unit(5) for details. When prefixed with an exclamation mark
("!"), the result is negated. If an empty string is assigned, the
previously assigned value is cleared.
Credential=
Checks whether the specified credential was passed to the
systemd-networkd.service service. See System and Service
Credentials[1] for details. When prefixed with an exclamation mark
("!"), the result is negated. If an empty string is assigned, the
previously assigned value is cleared.
Architecture=
Checks whether the system is running on a specific architecture.
See ConditionArchitecture= in systemd.unit(5) for details. When
prefixed with an exclamation mark ("!"), the result is negated. If
an empty string is assigned, the previously assigned value is
cleared.
Firmware=
Checks whether the system is running on a machine with the
specified firmware. See ConditionFirmware= in systemd.unit(5) for
details. When prefixed with an exclamation mark ("!"), the result
is negated. If an empty string is assigned, the previously assigned
value is cleared.
[LINK] SECTION OPTIONS
The [Link] section accepts the following keys:
Description=
A description of the device.
Alias=
The ifalias interface property is set to this value.
MACAddressPolicy=
The policy by which the MAC address should be set. The available
policies are:
persistent
If the hardware has a persistent MAC address, as most hardware
should, and if it is used by the kernel, nothing is done.
Otherwise, a new MAC address is generated which is guaranteed
to be the same on every boot for the given machine and the
given device, but which is otherwise random. This feature
depends on ID_NET_NAME_* properties to exist for the link. On
hardware where these properties are not set, the generation of
a persistent MAC address will fail.
random
If the kernel is using a random MAC address, nothing is done.
Otherwise, a new address is randomly generated each time the
device appears, typically at boot. Either way, the random
address will have the "unicast" and "locally administered" bits
set.
none
Keeps the MAC address assigned by the kernel. Or use the MAC
address specified in MACAddress=.
An empty string assignment is equivalent to setting "none".
MACAddress=
The interface MAC address to use. For this setting to take effect,
MACAddressPolicy= must either be unset, empty, or "none".
NamePolicy=
An ordered, space-separated list of policies by which the interface
name should be set. NamePolicy= may be disabled by specifying
net.ifnames=0 on the kernel command line. Each of the policies may
fail, and the first successful one is used. The name is not set
directly, but is exported to udev as the property ID_NET_NAME,
which is, by default, used by a udev(7), rule to set NAME. The
available policies are:
kernel
If the kernel claims that the name it has set for a device is
predictable, then no renaming is performed.
database
The name is set based on entries in the udev's Hardware
Database with the key ID_NET_NAME_FROM_DATABASE.
onboard
The name is set based on information given by the firmware for
on-board devices, as exported by the udev property
ID_NET_NAME_ONBOARD. See systemd.net-naming-scheme(7).
slot
The name is set based on information given by the firmware for
hot-plug devices, as exported by the udev property
ID_NET_NAME_SLOT. See systemd.net-naming-scheme(7).
path
The name is set based on the device's physical location, as
exported by the udev property ID_NET_NAME_PATH. See
systemd.net-naming-scheme(7).
mac
The name is set based on the device's persistent MAC address,
as exported by the udev property ID_NET_NAME_MAC. See
systemd.net-naming-scheme(7).
keep
If the device already had a name given by userspace (as part of
creation of the device or a rename), keep it.
Name=
The interface name to use. This option has lower precedence than
NamePolicy=, so for this setting to take effect, NamePolicy= must
either be unset, empty, disabled, or all policies configured there
must fail. Also see the example below with "Name=dmz0".
Note that specifying a name that the kernel might use for another
interface (for example "eth0") is dangerous because the name
assignment done by udev will race with the assignment done by the
kernel, and only one interface may use the name. Depending on the
order of operations, either udev or the kernel will win, making the
naming unpredictable. It is best to use some different prefix, for
example "internal0"/"external0" or "lan0"/"lan1"/"lan3".
Interface names must have a minimum length of 1 character and a
maximum length of 15 characters, and may contain any 7bit ASCII
character, with the exception of control characters, ":", "/" and
"%". While "." is an allowed character, it's recommended to avoid
it when naming interfaces as various tools (such as resolvconf(1))
use it as separator character. Also, fully numeric interface names
are not allowed (in order to avoid ambiguity with interface
specification by numeric indexes), as are the special strings ".",
"..", "all" and "default".
AlternativeNamesPolicy=
A space-separated list of policies by which the interface's
alternative names should be set. Each of the policies may fail, and
all successful policies are used. The available policies are
"database", "onboard", "slot", "path", and "mac". If the kernel
does not support the alternative names, then this setting will be
ignored.
AlternativeName=
The alternative interface name to use. This option can be specified
multiple times. If the empty string is assigned to this option, the
list is reset, and all prior assignments have no effect. If the
kernel does not support the alternative names, then this setting
will be ignored.
Alternative interface names may be used to identify interfaces in
various tools. In contrast to the primary name (as configured with
Name= above) there may be multiple alternative names referring to
the same interface. Alternative names may have a maximum length of
127 characters, in contrast to the 15 allowed for the primary
interface name, but otherwise are subject to the same naming
constraints.
TransmitQueues=
Specifies the device's number of transmit queues. An integer in the
range 1...4096. When unset, the kernel's default will be used.
ReceiveQueues=
Specifies the device's number of receive queues. An integer in the
range 1...4096. When unset, the kernel's default will be used.
TransmitQueueLength=
Specifies the transmit queue length of the device in number of
packets. An unsigned integer in the range 0...4294967294. When
unset, the kernel's default will be used.
MTUBytes=
The maximum transmission unit in bytes to set for the device. The
usual suffixes K, M, G are supported and are understood to the base
of 1024.
BitsPerSecond=
The speed to set for the device, the value is rounded down to the
nearest Mbps. The usual suffixes K, M, G are supported and are
understood to the base of 1000.
Duplex=
The duplex mode to set for the device. The accepted values are half
and full.
AutoNegotiation=
Takes a boolean. If set to yes, automatic negotiation of
transmission parameters is enabled. Autonegotiation is a procedure
by which two connected ethernet devices choose common transmission
parameters, such as speed, duplex mode, and flow control. When
unset, the kernel's default will be used.
Note that if autonegotiation is enabled, speed and duplex settings
are read-only. If autonegotiation is disabled, speed and duplex
settings are writable if the driver supports multiple link modes.
WakeOnLan=
The Wake-on-LAN policy to set for the device. Takes the special
value "off" which disables Wake-on-LAN, or space separated list of
the following words:
phy
Wake on PHY activity.
unicast
Wake on unicast messages.
multicast
Wake on multicast messages.
broadcast
Wake on broadcast messages.
arp
Wake on ARP.
magic
Wake on receipt of a magic packet.
secureon
Enable SecureOn password for MagicPacket. Implied when
WakeOnLanPassword= is specified. If specified without
WakeOnLanPassword= option, then the password is read from the
credential "LINK.link.wol.password" (e.g.,
"60-foo.link.wol.password"), and if the credential not found,
then read from "wol.password". See
LoadCredential=/SetCredential= in systemd.exec(1) for details.
The password in the credential, must be 6 bytes in hex format
with each byte separated by a colon (":") like an Ethernet MAC
address, e.g., "aa:bb:cc:dd:ee:ff".
Defaults to unset, and the device's default will be used. This
setting can be specified multiple times. If an empty string is
assigned, then the all previous assignments are cleared.
WakeOnLanPassword=
Specifies the SecureOn password for MagicPacket. Takes an absolute
path to a regular file or an AF_UNIX stream socket, or the plain
password. When a path to a regular file is specified, the password
is read from it. When an AF_UNIX stream socket is specified, a
connection is made to it and the password is read from it. The
password must be 6 bytes in hex format with each byte separated by
a colon (":") like an Ethernet MAC address, e.g.,
"aa:bb:cc:dd:ee:ff". This implies WakeOnLan=secureon. Defaults to
unset, and the current value will not be changed.
Port=
The port option is used to select the device port. The supported
values are:
tp
An Ethernet interface using Twisted-Pair cable as the medium.
aui
Attachment Unit Interface (AUI). Normally used with hubs.
bnc
An Ethernet interface using BNC connectors and co-axial cable.
mii
An Ethernet interface using a Media Independent Interface
(MII).
fibre
An Ethernet interface using Optical Fibre as the medium.
Advertise=
This sets what speeds and duplex modes of operation are advertised
for auto-negotiation. This implies "AutoNegotiation=yes". The
supported values are:
Table 1. Supported advertise values
┌───────────────────┬──────────────┬─────────────┐
│Advertise │ Speed (Mbps) │ Duplex Mode │
├───────────────────┼──────────────┼─────────────┤
│10baset-half │ 10 │ half │
├───────────────────┼──────────────┼─────────────┤
│10baset-full │ 10 │ full │
├───────────────────┼──────────────┼─────────────┤
│100baset-half │ 100 │ half │
├───────────────────┼──────────────┼─────────────┤
│100baset-full │ 100 │ full │
├───────────────────┼──────────────┼─────────────┤
│1000baset-half │ 1000 │ half │
├───────────────────┼──────────────┼─────────────┤
│1000baset-full │ 1000 │ full │
├───────────────────┼──────────────┼─────────────┤
│10000baset-full │ 10000 │ full │
├───────────────────┼──────────────┼─────────────┤
│2500basex-full │ 2500 │ full │
├───────────────────┼──────────────┼─────────────┤
│1000basekx-full │ 1000 │ full │
├───────────────────┼──────────────┼─────────────┤
│10000basekx4-full │ 10000 │ full │
├───────────────────┼──────────────┼─────────────┤
│10000basekr-full │ 10000 │ full │
├───────────────────┼──────────────┼─────────────┤
│10000baser-fec │ 10000 │ full │
├───────────────────┼──────────────┼─────────────┤
│20000basemld2-full │ 20000 │ full │
├───────────────────┼──────────────┼─────────────┤
│20000basekr2-full │ 20000 │ full │
└───────────────────┴──────────────┴─────────────┘
By default this is unset, i.e. all possible modes will be
advertised. This option may be specified more than once, in which
case all specified speeds and modes are advertised. If the empty
string is assigned to this option, the list is reset, and all prior
assignments have no effect.
ReceiveChecksumOffload=
Takes a boolean. If set to true, hardware offload for checksumming
of ingress network packets is enabled. When unset, the kernel's
default will be used.
TransmitChecksumOffload=
Takes a boolean. If set to true, hardware offload for checksumming
of egress network packets is enabled. When unset, the kernel's
default will be used.
TCPSegmentationOffload=
Takes a boolean. If set to true, TCP Segmentation Offload (TSO) is
enabled. When unset, the kernel's default will be used.
TCP6SegmentationOffload=
Takes a boolean. If set to true, TCP6 Segmentation Offload
(tx-tcp6-segmentation) is enabled. When unset, the kernel's default
will be used.
GenericSegmentationOffload=
Takes a boolean. If set to true, Generic Segmentation Offload (GSO)
is enabled. When unset, the kernel's default will be used.
GenericReceiveOffload=
Takes a boolean. If set to true, Generic Receive Offload (GRO) is
enabled. When unset, the kernel's default will be used.
GenericReceiveOffloadHardware=
Takes a boolean. If set to true, hardware accelerated Generic
Receive Offload (GRO) is enabled. When unset, the kernel's default
will be used.
LargeReceiveOffload=
Takes a boolean. If set to true, Large Receive Offload (LRO) is
enabled. When unset, the kernel's default will be used.
ReceiveVLANCTAGHardwareAcceleration=
Takes a boolean. If set to true, receive VLAN CTAG hardware
acceleration is enabled. When unset, the kernel's default will be
used.
TransmitVLANCTAGHardwareAcceleration=
Takes a boolean. If set to true, transmit VLAN CTAG hardware
acceleration is enabled. When unset, the kernel's default will be
used.
ReceiveVLANCTAGFilter=
Takes a boolean. If set to true, receive filtering on VLAN CTAGs is
enabled. When unset, the kernel's default will be used.
TransmitVLANSTAGHardwareAcceleration=
Takes a boolean. If set to true, transmit VLAN STAG hardware
acceleration is enabled. When unset, the kernel's default will be
used.
NTupleFilter=
Takes a boolean. If set to true, receive N-tuple filters and
actions are enabled. When unset, the kernel's default will be used.
RxChannels=, TxChannels=, OtherChannels=, CombinedChannels=
Specifies the number of receive, transmit, other, or combined
channels, respectively. Takes an unsigned integer in the range
1...4294967295 or "max". If set to "max", the advertised maximum
value of the hardware will be used. When unset, the number will not
be changed. Defaults to unset.
RxBufferSize=, RxMiniBufferSize=, RxJumboBufferSize=, TxBufferSize=
Specifies the maximum number of pending packets in the NIC receive
buffer, mini receive buffer, jumbo receive buffer, or transmit
buffer, respectively. Takes an unsigned integer in the range
1...4294967295 or "max". If set to "max", the advertised maximum
value of the hardware will be used. When unset, the number will not
be changed. Defaults to unset.
RxFlowControl=
Takes a boolean. When set, enables receive flow control, also known
as the ethernet receive PAUSE message (generate and send ethernet
PAUSE frames). When unset, the kernel's default will be used.
TxFlowControl=
Takes a boolean. When set, enables transmit flow control, also
known as the ethernet transmit PAUSE message (respond to received
ethernet PAUSE frames). When unset, the kernel's default will be
used.
AutoNegotiationFlowControl=
Takes a boolean. When set, auto negotiation enables the interface
to exchange state advertisements with the connected peer so that
the two devices can agree on the ethernet PAUSE configuration. When
unset, the kernel's default will be used.
GenericSegmentOffloadMaxBytes=
Specifies the maximum size of a Generic Segment Offload (GSO)
packet the device should accept. The usual suffixes K, M, G are
supported and are understood to the base of 1024. An unsigned
integer in the range 1...65536. Defaults to unset.
GenericSegmentOffloadMaxSegments=
Specifies the maximum number of Generic Segment Offload (GSO)
segments the device should accept. An unsigned integer in the range
1...65535. Defaults to unset.
UseAdaptiveRxCoalesce=, UseAdaptiveTxCoalesce=
Boolean properties that, when set, enable/disable adaptive Rx/Tx
coalescing if the hardware supports it. When unset, the kernel's
default will be used.
RxCoalesceSec=, RxCoalesceIrqSec=, RxCoalesceLowSec=,
RxCoalesceHighSec=, TxCoalesceSec=, TxCoalesceIrqSec=,
TxCoalesceLowSec=, TxCoalesceHighSec=
These properties configure the delay before Rx/Tx interrupts are
generated after a packet is sent/received. The "Irq" properties
come into effect when the host is servicing an IRQ. The "Low" and
"High" properties come into effect when the packet rate drops below
the low packet rate threshold or exceeds the high packet rate
threshold respectively if adaptive Rx/Tx coalescing is enabled.
When unset, the kernel's defaults will be used.
RxMaxCoalescedFrames=, RxMaxCoalescedIrqFrames=,
RxMaxCoalescedLowFrames=, RxMaxCoalescedHighFrames=,
TxMaxCoalescedFrames=, TxMaxCoalescedIrqFrames=,
TxMaxCoalescedLowFrames=, TxMaxCoalescedHighFrames=
These properties configure the maximum number of frames that are
sent/received before a Rx/Tx interrupt is generated. The "Irq"
properties come into effect when the host is servicing an IRQ. The
"Low" and "High" properties come into effect when the packet rate
drops below the low packet rate threshold or exceeds the high
packet rate threshold respectively if adaptive Rx/Tx coalescing is
enabled. When unset, the kernel's defaults will be used.
CoalescePacketRateLow=, CoalescePacketRateHigh=
These properties configure the low and high packet rate (expressed
in packets per second) threshold respectively and are used to
determine when the corresponding coalescing settings for low and
high packet rates come into effect if adaptive Rx/Tx coalescing is
enabled. If unset, the kernel's defaults will be used.
CoalescePacketRateSampleIntervalSec=
Configures how often to sample the packet rate used for adaptive
Rx/Tx coalescing. This property cannot be zero. This lowest time
granularity supported by this property is seconds. Partial seconds
will be rounded up before being passed to the kernel. If unset, the
kernel's default will be used.
StatisticsBlockCoalesceSec=
How long to delay driver in-memory statistics block updates. If the
driver does not have an in-memory statistic block, this property is
ignored. This property cannot be zero. If unset, the kernel's
default will be used.
MDI=
Specifies the medium dependent interface (MDI) mode for the
interface. A MDI describes the interface from a physical layer
implementation to the physical medium used to carry the
transmission. Takes one of the following words: "straight" (or
equivalently: "mdi"), "crossover" (or equivalently: "mdi-x",
"mdix"), and "auto". When "straight", the MDI straight through mode
will be used. When "crossover", the MDI crossover (MDI-X) mode will
be used. When "auto", the MDI status is automatically detected.
Defaults to unset, and the kernel's default will be used.
SR-IOVVirtualFunctions=
Specifies the number of SR-IOV virtual functions. Takes an integer
in the range 0...2147483647. Defaults to unset, and automatically
determined from the values specified in the VirtualFunction=
settings in the [SR-IOV] sections.
[SR-IOV] SECTION OPTIONS
The [SR-IOV] section accepts the following keys. Specify several
[SR-IOV] sections to configure several SR-IOVs. SR-IOV provides the
ability to partition a single physical PCI resource into virtual PCI
functions which can then be injected into a VM. In the case of network
VFs, SR-IOV improves north-south network performance (that is, traffic
with endpoints outside the host machine) by allowing traffic to bypass
the host machine’s network stack.
VirtualFunction=
Specifies a Virtual Function (VF), lightweight PCIe function
designed solely to move data in and out. Takes an integer in the
range 0...2147483646. This option is compulsory.
VLANId=
Specifies VLAN ID of the virtual function. Takes an integer in the
range 1...4095.
QualityOfService=
Specifies quality of service of the virtual function. Takes an
integer in the range 1...4294967294.
VLANProtocol=
Specifies VLAN protocol of the virtual function. Takes "802.1Q" or
"802.1ad".
MACSpoofCheck=
Takes a boolean. Controls the MAC spoof checking. When unset, the
kernel's default will be used.
QueryReceiveSideScaling=
Takes a boolean. Toggle the ability of querying the receive side
scaling (RSS) configuration of the virtual function (VF). The VF
RSS information like RSS hash key may be considered sensitive on
some devices where this information is shared between VF and the
physical function (PF). When unset, the kernel's default will be
used.
Trust=
Takes a boolean. Allows one to set trust mode of the virtual
function (VF). When set, VF users can set a specific feature which
may impact security and/or performance. When unset, the kernel's
default will be used.
LinkState=
Allows one to set the link state of the virtual function (VF).
Takes a boolean or a special value "auto". Setting to "auto" means
a reflection of the physical function (PF) link state, "yes" lets
the VF to communicate with other VFs on this host even if the PF
link state is down, "no" causes the hardware to drop any packets
sent by the VF. When unset, the kernel's default will be used.
MACAddress=
Specifies the MAC address for the virtual function.
EXAMPLES
Example 1. /lib/systemd/network/99-default.link
The link file 99-default.link that is shipped with systemd defines the
default naming policy for links.
[Link]
NamePolicy=kernel database onboard slot path
MACAddressPolicy=persistent
Example 2. /etc/systemd/network/10-dmz.link
This example assigns the fixed name "dmz0" to the interface with the
MAC address 00:a0:de:63:7a:e6:
[Match]
MACAddress=00:a0:de:63:7a:e6
[Link]
Name=dmz0
NamePolicy= is not set, so Name= takes effect. We use the "10-" prefix
to order this file early in the list. Note that it needs to be before
"99-link", i.e. it needs a numerical prefix, to have any effect at all.
Example 3. Debugging NamePolicy= assignments
$ sudo SYSTEMD_LOG_LEVEL=debug udevadm test-builtin net_setup_link /sys/class/net/hub0
...
Parsed configuration file /lib/systemd/network/99-default.link
Parsed configuration file /etc/systemd/network/10-eth0.link
ID_NET_DRIVER=cdc_ether
Config file /etc/systemd/network/10-eth0.link applies to device hub0
link_config: autonegotiation is unset or enabled, the speed and duplex are not writable.
hub0: Device has name_assign_type=4
Using default interface naming scheme 'v240'.
hub0: Policies didn't yield a name, using specified Name=hub0.
ID_NET_LINK_FILE=/etc/systemd/network/10-eth0.link
ID_NET_NAME=hub0
...
Explicit Name= configuration wins in this case.
sudo SYSTEMD_LOG_LEVEL=debug udevadm test-builtin net_setup_link /sys/class/net/enp0s31f6
...
Parsed configuration file /lib/systemd/network/99-default.link
Parsed configuration file /etc/systemd/network/10-eth0.link
Created link configuration context.
ID_NET_DRIVER=e1000e
Config file /lib/systemd/network/99-default.link applies to device enp0s31f6
link_config: autonegotiation is unset or enabled, the speed and duplex are not writable.
enp0s31f6: Device has name_assign_type=4
Using default interface naming scheme 'v240'.
enp0s31f6: Policy *keep*: keeping existing userspace name
enp0s31f6: Device has addr_assign_type=0
enp0s31f6: MAC on the device already matches policy *persistent*
ID_NET_LINK_FILE=/lib/systemd/network/99-default.link
...
In this case, the interface was already renamed, so the keep policy
specified as the first option in 99-default.link means that the
existing name is preserved. If keep was removed, or if were in boot
before the renaming has happened, we might get the following instead:
enp0s31f6: Policy *path* yields "enp0s31f6".
enp0s31f6: Device has addr_assign_type=0
enp0s31f6: MAC on the device already matches policy *persistent*
ID_NET_LINK_FILE=/lib/systemd/network/99-default.link
ID_NET_NAME=enp0s31f6
...
Please note that the details of output are subject to change.
Example 4. /etc/systemd/network/10-internet.link
This example assigns the fixed name "internet0" to the interface with
the device path "pci-0000:00:1a.0-*":
[Match]
Path=pci-0000:00:1a.0-*
[Link]
Name=internet0
Example 5. /etc/systemd/network/25-wireless.link
Here's an overly complex example that shows the use of a large number
of [Match] and [Link] settings.
[Match]
MACAddress=12:34:56:78:9a:bc
Driver=brcmsmac
Path=pci-0000:02:00.0-*
Type=wlan
Virtualization=no
Host=my-laptop
Architecture=x86-64
[Link]
Name=wireless0
MTUBytes=1450
BitsPerSecond=10M
WakeOnLan=magic
MACAddress=cb:a9:87:65:43:21
SEE ALSO
systemd-udevd.service(8), udevadm(8), systemd.netdev(5),
systemd.network(5), systemd-network-generator.service(8)
NOTES
1. System and Service Credentials
https://systemd.io/CREDENTIALS
systemd 252 SYSTEMD.LINK(5)
Generated by dwww version 1.15 on Wed Jun 26 01:08:43 CEST 2024.