Man Pages

IP−LINK


NAME
SYNOPSIS
DESCRIPTION
EXAMPLES
SEE ALSO
AUTHOR

NAME

ip-link − network device configuration

SYNOPSIS

ip [ OPTIONS ] link { COMMAND | help }

OPTIONS := { −V[ersion] | −h[uman-readable] | −s[tatistics] | −r[esolve] | −f[amily] { inet | inet6 | ipx | dnet | link } | −o[neline] | −br[ief] }

ip link add [ link DEVICE ] [ name ] NAME
[ txqueuelen PACKETS ]
[ address LLADDR ] [ broadcast LLADDR ]
[ mtu MTU ] [ index IDX ]
[ numtxqueues QUEUE_COUNT ] [ numrxqueues QUEUE_COUNT ]
type
TYPE [ ARGS ]

TYPE := [ bridge | bond | can | dummy | hsr | ifb | ipoib | macvlan | macvtap | vcan | veth | vlan | vxlan | ip6tnl | ipip | sit | gre | gretap | ip6gre | ip6gretap | vti | nlmon | ipvlan | lowpan | geneve ]

ip link delete { DEVICE | group GROUP } type TYPE [ ARGS ]

ip link set { DEVICE | group GROUP } { up | down | arp { on | off } |
promisc
{ on | off } |
allmulticast
{ on | off } |
dynamic
{ on | off } |
multicast
{ on | off } |
protodown
{ on | off } |
txqueuelen
PACKETS |
name
NEWNAME |
address
LLADDR | broadcast LLADDR |
mtu
MTU |
netns
PID |
netns
NETNSNAME |
alias
NAME |
vf
NUM [ mac LLADDR ] [ vlan VLANID [ qos VLAN-QOS ] ] [ rate TXRATE ] [ max_tx_rate TXRATE ] [ min_tx_rate TXRATE ] [ spoofchk { on | off } ] [ state { auto | enable | disable} ] [ trust { on | off } ] |
master
DEVICE |
nomaster |
addrgenmode { eui64 | none }
link-netnsid ID }

ip link show [ DEVICE | group GROUP | up | master DEVICE | type TYPE ]

ip link help [ TYPE ]

DESCRIPTION

ip link add - add virtual link
link
DEVICE

specifies the physical device to act operate on.

NAME specifies the name of the new virtual device.

TYPE specifies the type of the new device.

Link types:

bridge - Ethernet Bridge device

bond - Bonding device can - Controller Area Network interface

dummy - Dummy network interface

hsr - High-availability Seamless Redundancy device

ifb - Intermediate Functional Block device

ipoib - IP over Infiniband device

macvlan - Virtual interface base on link layer address (MAC)

macvtap - Virtual interface based on link layer address (MAC) and TAP.

vcan - Virtual Controller Area Network interface

veth - Virtual ethernet interface

vlan - 802.1q tagged virtual LAN interface

vxlan - Virtual eXtended LAN

ip6tnl - Virtual tunnel interface IPv4|IPv6 over IPv6

ipip - Virtual tunnel interface IPv4 over IPv4

sit - Virtual tunnel interface IPv6 over IPv4

gre - Virtual tunnel interface GRE over IPv4

gretap - Virtual L2 tunnel interface GRE over IPv4

ip6gre - Virtual tunnel interface GRE over IPv6

ip6gretap - Virtual L2 tunnel interface GRE over IPv6

vti - Virtual tunnel interface

nlmon - Netlink monitoring device

ipvlan - Interface for L3 (IPv6/IPv4) based VLANs

lowpan - Interface for 6LoWPAN (IPv6) over IEEE 802.15.4 / Bluetooth

geneve - GEneric NEtwork Virtualization Encapsulation

numtxqueues QUEUE_COUNT

specifies the number of transmit queues for new device.

numrxqueues QUEUE_COUNT

specifies the number of receive queues for new device.

index IDX

specifies the desired index of the new virtual device. The link creation fails, if the index is busy.

VLAN Type Support

For a link of type VLAN the following additional arguments are supported:

ip link add link DEVICE name NAME type vlan [ protocol VLAN_PROTO ] id VLANID [ reorder_hdr { on | off } ] [ gvrp { on | off } ] [ mvrp { on | off } ] [ loose_binding { on | off } ] [ ingress-qos-map QOS-MAP ] [ egress-qos-map QOS-MAP ]

protocol VLAN_PROTO - either 802.1Q or 802.1ad.

id VLANID - specifies the VLAN Identifer to use. Note that numbers with a leading " 0 " or " 0x " are interpreted as octal or hexadeimal, respectively.

reorder_hdr { on | off } - specifies whether ethernet headers are reordered or not (default is on).

If reorder_hdr is on then VLAN header will be not inserted immediately but only before passing to the physical device (if this device does not support VLAN offloading), the similar on the RX direction - by default the packet will be untagged before being received by VLAN device. Reordering allows to accelerate tagging on egress and to hide VLAN header on ingress so the packet looks like regular Ethernet packet, at the same time it might be confusing for packet capture as the VLAN header does not exist within the packet.

VLAN offloading can be checked by ethtool(8):

ethtool -k <phy_dev> | grep tx-vlan-offload

where <phy_dev> is the physical device to which VLAN device is bound.

gvrp { on | off } - specifies whether this VLAN should be registered using GARP VLAN Registration Protocol.

mvrp { on | off } - specifies whether this VLAN should be registered using Multiple VLAN Registration Protocol.

loose_binding { on | off } - specifies whether the VLAN device state is bound to the physical device state.

ingress-qos-map QOS-MAP - defines a mapping of VLAN header prio field to the Linux internal packet priority on incoming frames. The format is FROM:TO with multiple mappings separated by spaces.

egress-qos-map QOS-MAP - defines a mapping of Linux internal packet priority to VLAN header prio field but for outgoing frames. The format is the same as for ingress-qos-map.

Linux packet priority can be set by iptables(8):

iptables -t mangle -A POSTROUTING [...] -j CLASSIFY --set-class 0:4

and this "4" priority can be used in the egress qos mapping to set VLAN prio "5":

ip link set veth0.10 type vlan egress 4:5

VXLAN Type Support

For a link of type VXLAN the following additional arguments are supported:

ip link add DEVICE type vxlan id ID [ dev PHYS_DEV ] [ { group | remote } IPADDR ] [ local IPADDR ] [ ttl TTL ] [ tos TOS ] [ dstport PORT ] [ srcport MIN MAX ] [ [no]learning ] [ [no]proxy ] [ [no]rsc ] [ [no]l2miss ] [ [no]l3miss ] [ [no]udpcsum ] [ [no]udp6zerocsumtx ] [ [no]udp6zerocsumrx ] [ ageing SECONDS ] [ maxaddress NUMBER ] [ gbp ]

id VNI - specifies the VXLAN Network Identifer (or VXLAN Segment Identifier) to use.

dev PHYS_DEV - specifies the physical device to use for tunnel endpoint communication.

group IPADDR - specifies the multicast IP address to join. This parameter cannot be specified with the remote parameter.

remote IPADDR - specifies the unicast destination IP address to use in outgoing packets when the destination link layer address is not known in the VXLAN device forwarding database. This parameter cannot be specified with the group parameter.

local IPADDR - specifies the source IP address to use in outgoing packets.

ttl TTL - specifies the TTL value to use in outgoing packets.

tos TOS - specifies the TOS value to use in outgoing packets.

dstport PORT - specifies the UDP destination port to communicate to the remote VXLAN tunnel endpoint.

srcport MIN MAX - specifies the range of port numbers to use as UDP source ports to communicate to the remote VXLAN tunnel endpoint.

[no]learning - specifies if unknown source link layer addresses and IP addresses are entered into the VXLAN device forwarding database.

[no]rsc - specifies if route short circuit is turned on.

[no]proxy - specifies ARP proxy is turned on.

[no]l2miss - specifies if netlink LLADDR miss notifications are generated.

[no]l3miss - specifies if netlink IP ADDR miss notifications are generated.

[no]udpcsum - specifies if UDP checksum is filled in

[no]udp6zerocsumtx - specifies if UDP checksum is filled in

[no]udp6zerocsumrx - specifies if UDP checksum is received

ageing SECONDS - specifies the lifetime in seconds of FDB entries learnt by the kernel.

maxaddress NUMBER - specifies the maximum number of FDB entries.

gbp - enables the Group Policy extension (VXLAN-GBP).

Allows to transport group policy context across VXLAN network peers. If enabled, includes the mark of a packet in the VXLAN header for outgoing packets and fills the packet mark based on the information found in the VXLAN header for incomming packets.

Format of upper 16 bits of packet mark (flags);

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|-|-|-|-|-|-|-|-|-|D|-|-|A|-|-|-|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

D := Don’t Learn bit. When set, this bit indicates that the egress VTEP MUST NOT learn the source address of the encapsulated frame.

A := Indicates that the group policy has already been applied to this packet. Policies MUST NOT be applied by devices when the A bit is set.

Format of lower 16 bits of packet mark (policy ID):

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Group Policy ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Example:
iptables -A OUTPUT [...] -j MARK --set-mark 0x800FF

GRE, IPIP, SIT Type Support

For a link of types GRE/IPIP/SIT the following additional arguments are supported:

ip link add DEVICE type { gre | ipip | sit } remote ADDR local ADDR [ encap { fou | gue | none } ] [ encap-sport { PORT | auto } ] [ encap-dport PORT ] [ [no]encap-csum ] [ [no]encap-remcsum ]

remote ADDR - specifies the remote address of the tunnel.

local ADDR - specifies the fixed local address for tunneled packets. It must be an address on another interface on this host.

encap { fou | gue | none } - specifies type of secondary UDP encapsulation. "fou" indicates Foo-Over-UDP, "gue" indicates Generic UDP Encapsulation.

encap-sport { PORT | auto } - specifies the source port in UDP encapsulation. PORT indicates the port by number, "auto" indicates that the port number should be chosen automatically (the kernel picks a flow based on the flow hash of the encapsulated packet).

[no]encap-csum - specifies if UDP checksums are enabled in the secondary encapsulation.

[no]encap-remcsum - specifies if Remote Checksum Offload is enabled. This is only applicable for Generic UDP Encapsulation.

IP6GRE/IP6GRETAP Type Support

For a link of type IP6GRE/IP6GRETAP the following additional arguments are supported:

ip link add DEVICE type { ip6gre | ip6gretap } remote ADDR local ADDR [ [i|o]seq] ] [ [i|o]key KEY ] [ [i|o]csum ] [ hoplimit TTL ] [ encaplimit ELIM ] [ tclass TCLASS ] [ flowlabel FLOWLABEL ] [ dscp inherit ] [ dev PHYS_DEV ]

remote ADDR - specifies the remote IPv6 address of the tunnel.

local ADDR - specifies the fixed local IPv6 address for tunneled packets. It must be an address on another interface on this host.

[i|o]seq - serialize packets. The oseq flag enables sequencing of outgoing packets. The iseq flag requires that all input packets are serialized.

[i|o]key KEY - use keyed GRE with key KEY. KEY is either a number or an IPv4 address-like dotted quad. The key parameter specifies the same key to use in both directions. The ikey and okey parameters specify different keys for input and output.

[i|o]csum - generate/require checksums for tunneled packets. The ocsum flag calculates checksums for outgoing packets. The icsum flag requires that all input packets have the correct checksum. The csum flag is equivalent to the combination icsum ocsum.

hoplimit TTL - specifies Hop Limit value to use in outgoing packets.

encaplimit ELIM - specifies a fixed encapsulation limit. Default is 4.

flowlabel FLOWLABEL - specifies a fixed flowlabel.

tclass TCLASS - specifies the traffic class field on tunneled packets, which can be specified as either a two-digit hex value (e.g. c0) or a predefined string (e.g. internet). The value inherit causes the field to be copied from the original IP header. The values inherit/STRING or inherit/00..ff will set the field to STRING or 00..ff when tunneling non-IP packets. The default value is 00.

IPoIB Type Support

For a link of type IPoIB the following additional arguments are supported:

ip link add DEVICE name NAME type ipoib [ pkey PKEY ] [mode MODE ]

pkey PKEY - specifies the IB P-Key to use.

mode MODE - specifies the mode (datagram or connected) to use.

GENEVE Type Support

For a link of type GENEVE the following additional arguments are supported:

ip link add DEVICE type geneve id ID remote IPADDR [ ttl TTL ] [ tos TOS ]

id VNI - specifies the Virtual Network Identifer to use.

remote IPADDR - specifies the unicast destination IP address to use in outgoing packets.

ttl TTL - specifies the TTL value to use in outgoing packets.

tos TOS - specifies the TOS value to use in outgoing packets.

MACVLAN and MACVTAP Type Support

For a link of type MACVLAN or MACVTAP the following additional arguments are supported:

ip link add link DEVICE name NAME type { macvlan | macvtap } mode { private | vepa | bridge | passthru [ nopromisc ] }

type { macvlan | macvtap } - specifies the link type to use. macvlan creates just a virtual interface, while macvtap in addition creates a character device /dev/tapX to be used just like a tuntap device.

mode private - Do not allow communication between macvlan instances on the same physical interface, even if the external switch supports hairpin mode.

mode vepa - Virtual Ethernet Port Aggregator mode. Data from one macvlan instance to the other on the same physical interface is transmitted over the physical interface. Either the attached switch needs to support hairpin mode, or there must be a TCP/IP router forwarding the packets in order to allow communication. This is the default mode.

mode bridge - In bridge mode, all endpoints are directly connected to each other, communication is not redirected through the physical interface’s peer.

mode passthru [ nopromisc ] - This mode gives more power to a single endpoint, usually in macvtap mode. It is not allowed for more than one endpoint on the same physical interface. All traffic will be forwarded to this endpoint, allowing virtio guests to change MAC address or set promiscuous mode in order to bridge the interface or create vlan interfaces on top of it. By default, this mode forces the underlying interface into promiscuous mode. Passing the nopromisc flag prevents this, so the promisc flag may be controlled using standard tools.

ip link delete - delete virtual link
dev
DEVICE

specifies the virtual device to act operate on.

group GROUP

specifies the group of virtual links to delete. Group 0 is not allowed to be deleted since it is the default group.

type TYPE

specifies the type of the device.

ip link set - change device attributes
dev
DEVICE

DEVICE specifies network device to operate on. When configuring SR-IOV Virtual Function (VF) devices, this keyword should specify the associated Physical Function (PF) device.

group GROUP

GROUP has a dual role: If both group and dev are present, then move the device to the specified group. If only a group is specified, then the command operates on all devices in that group.

up and down

change the state of the device to UP or DOWN.

arp on or arp off

change the NOARP flag on the device.

multicast on or multicast off

change the MULTICAST flag on the device.

protodown on or protodown off

change the PROTODOWN state on the device. Indicates that a protocol error has been detected on the port. Switch drivers can react to this error by doing a phys down on the switch port.

dynamic on or dynamic off

change the DYNAMIC flag on the device. Indicates that address can change when interface goes down (currently NOT used by the Linux).

name NAME

change the name of the device. This operation is not recommended if the device is running or has some addresses already configured.

txqueuelen NUMBER
txqlen
NUMBER

change the transmit queue length of the device.

mtu NUMBER

change the MTU of the device.

address LLADDRESS

change the station address of the interface.

broadcast LLADDRESS
brd
LLADDRESS
peer
LLADDRESS

change the link layer broadcast address or the peer address when the interface is POINTOPOINT.

netns NETNSNAME | PID

move the device to the network namespace associated with name NETNSNAME or process PID.

Some devices are not allowed to change network namespace: loopback, bridge, ppp, wireless. These are network namespace local devices. In such case ip tool will return "Invalid argument" error. It is possible to find out if device is local to a single network namespace by checking netns-local flag in the output of the ethtool:

ethtool -k DEVICE

To change network namespace for wireless devices the iw tool can be used. But it allows to change network namespace only for physical devices and by process PID.

alias NAME

give the device a symbolic name for easy reference.

group GROUP

specify the group the device belongs to. The available groups are listed in file /etc/iproute2/group.

vf NUM

specify a Virtual Function device to be configured. The associated PF device must be specified using the dev parameter.

mac LLADDRESS - change the station address for the specified VF. The vf parameter must be specified.

vlan VLANID - change the assigned VLAN for the specified VF. When specified, all traffic sent from the VF will be tagged with the specified VLAN ID. Incoming traffic will be filtered for the specified VLAN ID, and will have all VLAN tags stripped before being passed to the VF. Setting this parameter to 0 disables VLAN tagging and filtering. The vf parameter must be specified.

qos VLAN-QOS - assign VLAN QOS (priority) bits for the VLAN tag. When specified, all VLAN tags transmitted by the VF will include the specified priority bits in the VLAN tag. If not specified, the value is assumed to be 0. Both the vf and vlan parameters must be specified. Setting both vlan and qos as 0 disables VLAN tagging and filtering for the VF.

rate TXRATE -- change the allowed transmit bandwidth, in Mbps, for the specified VF. Setting this parameter to 0 disables rate limiting. vf parameter must be specified. Please use new API max_tx_rate option instead.

max_tx_rate TXRATE - change the allowed maximum transmit bandwidth, in Mbps, for the specified VF. vf parameter must be specified.

min_tx_rate TXRATE - change the allowed minimum transmit bandwidth, in Mbps, for the specified VF. Minimum TXRATE should be always <= Maximum TXRATE. vf parameter must be specified.

spoofchk on|off - turn packet spoof checking on or off for the specified VF.

state auto|enable|disable - set the virtual link state as seen by the specified VF. Setting to auto means a reflection of the PF link state, enable lets the VF to communicate with other VFs on this host even if the PF link state is down, disable causes the HW to drop any packets sent by the VF.

trust on|off - trust the specified VF user. This enables that VF user can set a specific feature which may impact security and/or performance. (e.g. VF multicast promiscuous mode)

master DEVICE

set master device of the device (enslave device).

nomaster

unset master device of the device (release device).

addrgenmode eui64 or addrgenmode none

set IPv6 address generation mode

link-netnsid

set peer netnsid for a cross-netns interface

Warning: If multiple parameter changes are requested, ip aborts immediately after any of the changes have failed. This is the only case when ip can move the system to an unpredictable state. The solution is to avoid changing several parameters with one ip link set call.

ip link show - display device attributes
dev
NAME (default)

NAME specifies the network device to show. If this argument is omitted all devices in the default group are listed.

group GROUP

GROUP specifies what group of devices to show.

up

only display running interfaces.

master DEVICE

DEVICE specifies the master device which enslaves devices to show.

type TYPE

TYPE specifies the type of devices to show.

The show command has additional formatting options:

−s, −stats, −statistics

output more statistics about packet usage.

−d, −details

output more detailed information.

−h, −human, −human-readable

output statistics with human readable values number followed by suffix

−iec

print human readable rates in IEC units (ie. 1K = 1024).

ip link help - display help
TYPE
specifies which help of link type to dislpay.

GROUP
may be a number or a string from the file /etc/iproute2/group which can be manually filled.

EXAMPLES

ip link show

Shows the state of all network interfaces on the system.

ip link show type bridge

Shows the bridge devices.

ip link show type vlan

Shows the vlan devices.

ip link show master br0

Shows devices enslaved by br0

ip link set dev ppp0 mtu 1400

Change the MTU the ppp0 device.

ip link add link eth0 name eth0.10 type vlan id 10

Creates a new vlan device eth0.10 on device eth0.

ip link delete dev eth0.10

Removes vlan device.

ip link help gre

Display help for the gre link type.

ip link add name tun1 type ipip remote 192.168.1.1 local 192.168.1.2 ttl 225 encap gue encap-sport auto encap-dport 5555 encap-csum encap-remcsum

Creates an IPIP that is encapsulated with Generic UDP Encapsulation, and the outer UDP checksum and remote checksum offload are enabled.

ip link add link wpan0 lowpan0 type lowpan

Creates a 6LoWPAN interface named lowpan0 on the underlying IEEE 802.15.4 device wpan0.

SEE ALSO

ip(8), ip-netns(8), ethtool(8), iptables(8)

AUTHOR

Original Manpage by Michail Litvak <mci@owl.openwall.com>

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