systemd.link (original) (raw)

Description=¶

A description of the device.

Added in version 211.

Property=¶

Set specified udev properties. This takes space separated list of key-value pairs concatenated with equal sign ("="). Example:

Property=HOGE=foo BAR=baz

This option supports simple specifier expansion, see the Specifiers section below. This option can be specified multiple times. If an empty string is assigned, then the all previous assignments are cleared.

This setting is useful to configure the "ID_NET_MANAGED_BY=" property which declares which network management service shall manage the interface, which is respected bysystemd-networkd and others. Use

Property=ID_NET_MANAGED_BY=io.systemd.Network

to declare explicitly that systemd-networkd shall manage the interface, or set the property to something else to declare explicitly it shall not do so. Seesystemd.network(5) for details how this property is used to match interface names.

Added in version 256.

ImportProperty=¶

Import specified udev properties from the saved database. This takes space separated list of property names. Example:

ImportProperty=HOGE BAR

This option supports simple specifier expansion, see the Specifiers section below. This option can be specified multiple times. If an empty string is assigned, then the all previous assignments are cleared.

If the same property is also set in Property= in the above, then the imported property value will be overridden by the value specified in Property=.

Added in version 256.

UnsetProperty=¶

Unset specified udev properties. This takes space separated list of property names. Example:

ImportProperty=HOGE BAR

This option supports simple specifier expansion, see the Specifiers section below. This option can be specified multiple times. If an empty string is assigned, then the all previous assignments are cleared.

This setting is applied after ImportProperty= andProperty= are applied. Hence, if the same property is specified inImportProperty= or Property=, then the imported or specified property value will be ignored, and the property will be unset.

Added in version 256.

Alias=¶

The ifalias interface property is set to this value.

Added in version 211.

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.

Added in version 211.

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.

Added in version 211.

none¶

Keeps the MAC address assigned by the kernel. Or use the MAC address specified inMACAddress=.

Added in version 227.

An empty string assignment is equivalent to setting "none".

Added in version 211.

MACAddress=¶

The interface MAC address to use. For this setting to take effect,MACAddressPolicy= must either be unset, empty, or "none".

Added in version 211.

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 audev(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.

Added in version 216.

database¶

The name is set based on entries in the udev's Hardware Database with the keyID_NET_NAME_FROM_DATABASE.

Added in version 211.

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).

Added in version 211.

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).

Added in version 211.

path¶

The name is set based on the device's physical location, as exported by the udev propertyID_NET_NAME_PATH. See systemd.net-naming-scheme(7).

Added in version 211.

mac¶

The name is set based on the device's persistent MAC address, as exported by the udev propertyID_NET_NAME_MAC. See systemd.net-naming-scheme(7).

Added in version 211.

keep¶

If the device already had a name given by userspace (as part of creation of the device or a rename), keep it.

Added in version 241.

Added in version 211.

Name=¶

The interface name to use. This option has lower precedence thanNamePolicy=, 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 asresolvconf(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), nor are the special strings ".", "..", "all" and "default".

Added in version 211.

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.

Added in version 245.

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.

Added in version 245.

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.

Added in version 248.

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.

Added in version 248.

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.

Added in version 248.

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.

Added in version 211.

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.

Added in version 211.

Duplex=¶

The duplex mode to set for the device. The accepted values are half andfull.

Added in version 211.

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.

Added in version 233.

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.

Added in version 211.

unicast¶

Wake on unicast messages.

Added in version 235.

multicast¶

Wake on multicast messages.

Added in version 235.

broadcast¶

Wake on broadcast messages.

Added in version 235.

arp¶

Wake on ARP.

Added in version 235.

magic¶

Wake on receipt of a magic packet.

Added in version 211.

secureon¶

Enable SecureOn password for MagicPacket. Implied whenWakeOnLanPassword= is specified. If specified withoutWakeOnLanPassword= 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". SeeImportCredential=/LoadCredential=/SetCredential= insystemd.exec(5) 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".

Added in version 235.

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.

Added in version 211.

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 anAF_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.

Added in version 250.

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.

Added in version 234.

aui¶

Attachment Unit Interface (AUI). Normally used with hubs.

Added in version 234.

bnc¶

An Ethernet interface using BNC connectors and co-axial cable.

Added in version 234.

mii¶

An Ethernet interface using a Media Independent Interface (MII).

Added in version 234.

fibre¶

An Ethernet interface using Optical Fibre as the medium.

Added in version 234.

Added in version 234.

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

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.

Added in version 240.

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.

Added in version 245.

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.

Added in version 245.

TCPSegmentationOffload=¶

Takes a boolean. If set to true, TCP Segmentation Offload (TSO) is enabled. When unset, the kernel's default will be used.

Added in version 232.

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.

Added in version 235.

GenericSegmentationOffload=¶

Takes a boolean. If set to true, Generic Segmentation Offload (GSO) is enabled. When unset, the kernel's default will be used.

Added in version 232.

GenericReceiveOffload=¶

Takes a boolean. If set to true, Generic Receive Offload (GRO) is enabled. When unset, the kernel's default will be used.

Added in version 232.

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.

Added in version 250.

LargeReceiveOffload=¶

Takes a boolean. If set to true, Large Receive Offload (LRO) is enabled. When unset, the kernel's default will be used.

Added in version 232.

ReceivePacketSteeringCPUMask=¶

Configures Receive Packet Steering (RPS) list of CPUs to which RPS may forward traffic. Takes a list of CPU indices or ranges separated by either whitespace or commas. Alternatively, takes the special value "all", which will include all available CPUs in the mask. CPU ranges are specified by the lower and upper CPU indices separated by a dash (e.g. "2-6"). This option may be specified more than once, in which case the specified list of CPU ranges are merged. If an empty string is assigned, the list is reset, all assignments prior to this will have no effect. Defaults to unset and RPS CPU list is unchanged. To disable RPS when it was previously enabled, use the special value "disable".

Added in version 256.

ReceiveVLANCTAGHardwareAcceleration=¶

Takes a boolean. If set to true, receive VLAN CTAG hardware acceleration is enabled. When unset, the kernel's default will be used.

Added in version 250.

TransmitVLANCTAGHardwareAcceleration=¶

Takes a boolean. If set to true, transmit VLAN CTAG hardware acceleration is enabled. When unset, the kernel's default will be used.

Added in version 250.

ReceiveVLANCTAGFilter=¶

Takes a boolean. If set to true, receive filtering on VLAN CTAGs is enabled. When unset, the kernel's default will be used.

Added in version 250.

TransmitVLANSTAGHardwareAcceleration=¶

Takes a boolean. If set to true, transmit VLAN STAG hardware acceleration is enabled. When unset, the kernel's default will be used.

Added in version 250.

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.

Added in version 250.

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.

Added in version 239.

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.

Added in version 244.

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.

Added in version 246.

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.

Added in version 246.

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.

Added in version 246.

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.

Added in version 248.

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.

Added in version 248.

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.

Added in version 250.

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.

Added in version 250.

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.

Added in version 250.

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.

Added in version 250.

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.

Added in version 250.

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.

Added in version 250.

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.

Added in version 251.

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.

Added in version 251.