| BRIDGE(8) | Linux | BRIDGE(8) |
bridge - show / manipulate bridge addresses and devices
bridge [ OPTIONS ] OBJECT { COMMAND | help }
OBJECT := { link | fdb | mdb | vlan | vni | monitor }
OPTIONS := { -V[ersion] | -s[tatistics] | -n[etns] name | -b[atch] filename | -c[olor] | -p[retty] | -j[son] | -o[neline] }
bridge link set dev DEV [ cost COST ] [ priority PRIO ] [ state STATE ] [ guard { on | off } ] [ hairpin { on | off } ] [ fastleave { on | off } ] [ root_block { on | off } ] [ learning { on | off } ] [ learning_sync { on | off } ] [ flood { on | off } ] [ hwmode { vepa | veb } ] [ bcast_flood { on | off } ] [ mcast_flood { on | off } ] [ mcast_router MULTICAST_ROUTER ] [ mcast_to_unicast { on | off } ] [ neigh_suppress { on | off } ] [ vlan_tunnel { on | off } ] [ isolated { on | off } ] [ locked { on | off } ] [ backup_port DEVICE ] [ nobackup_port ] [ self ] [ master ]
bridge link [ show ] [ dev DEV ]
bridge fdb { add | append | del | replace } LLADDR dev DEV { local | static | dynamic } [ self ] [ master ] [ router ] [ use ] [ extern_learn ] [ sticky ] [ src_vni VNI ] { [ dst IPADDR ] [ vni VNI ] [ port PORT ] [ via DEVICE ] | nhid NHID }
bridge fdb [ [ show ] [ br BRDEV ] [ brport DEV ] [ vlan VID ] [ state STATE ] [ dynamic ] ]
bridge fdb get [ to ] LLADDR [ br BRDEV ] { brport | dev } DEV [ vlan VID ] [ vni VNI ] [ self ] [ master ] [ dynamic ]
bridge fdb flush dev DEV [ brport DEV ] [ vlan VID ] [ self ] [ master ] [ [no]permanent | [no]static | [no]dynamic ] [ [no]added_by_user ] [ [no]extern_learn ] [ [no]sticky ] [ [no]offloaded ]
bridge mdb { add | del } dev DEV port PORT grp GROUP [ src SOURCE ] [ permanent | temp ] [ vid VID ]
bridge mdb show [ dev DEV ]
bridge vlan { add | del } dev DEV vid VID [ tunnel_info TUNNEL_ID ] [ pvid ] [ untagged ] [ self ] [ master ]
bridge vlan set dev DEV vid VID [ state STP_STATE ] [ mcast_router MULTICAST_ROUTER ]
bridge vlan [ show | tunnelshow ] [ dev DEV ]
bridge vlan global set dev DEV vid VID [ mcast_snooping MULTICAST_SNOOPING ] [ mcast_querier MULTICAST_QUERIER ] [ mcast_igmp_version IGMP_VERSION ] [ mcast_mld_version MLD_VERSION ] [ mcast_last_member_count LAST_MEMBER_COUNT ] [ mcast_last_member_interval LAST_MEMBER_INTERVAL ] [ mcast_startup_query_count STARTUP_QUERY_COUNT ] [ mcast_startup_query_interval STARTUP_QUERY_INTERVAL ] [ mcast_membership_interval MEMBERSHIP_INTERVAL ] [ mcast_querier_interval QUERIER_INTERVAL ] [ mcast_query_interval QUERY_INTERVAL ] [ mcast_query_response_interval QUERY_RESPONSE_INTERVAL ]
bridge vlan global [ show ] [ dev DEV ] [ vid VID ]
bridge vlan show [ dev DEV ]
bridge vni { add | del } dev DEV vni VNI [ { group | remote } IPADDR ]
bridge vni show [ dev DEV ]
bridge monitor [ all | neigh | link | mdb | vlan ]
ip netns exec NETNS bridge [ OPTIONS ] OBJECT { COMMAND | help }
to
bridge -n[etns] NETNS [ OPTIONS ] OBJECT { COMMAND | help }
Specifies the action to perform on the object. The set of possible actions depends on the object type. As a rule, it is possible to add, delete and show (or list ) objects, but some objects do not allow all of these operations or have some additional commands. The help command is available for all objects. It prints out a list of available commands and argument syntax conventions.
If no command is given, some default command is assumed. Usually it is list or, if the objects of this class cannot be listed, help.
link objects correspond to the port devices of the bridge.
The corresponding commands set and display port status and bridge specific attributes.
0 - port is in STP DISABLED state. Make this port completely inactive for STP. This is also called BPDU filter and could be used to disable STP on an untrusted port, like a leaf virtual devices.
1 - port is in STP LISTENING state. Only valid if STP is enabled on the bridge. In this state the port listens for STP BPDUs and drops all other traffic frames.
2 - port is in STP LEARNING state. Only valid if STP is enabled on the bridge. In this state the port will accept traffic only for the purpose of updating MAC address tables.
3 - port is in STP FORWARDING state. Port is fully active.
4 - port is in STP BLOCKING state. Only valid if STP is enabled on the bridge. This state is used during the STP election process. In this state, port will only process STP BPDUs.
If running Spanning Tree on bridge, hostile devices on the network may send BPDU on a port and cause network failure. Setting guard on will detect and stop this by disabling the port. The port will be restarted if link is brought down, or removed and reattached. For example if guard is enable on eth0:
ip link set dev eth0 down; ip link set dev eth0 up
This feature is also called root port guard. If BPDU is received from a leaf (edge) port, it should not be elected as root port. This could be used if using STP on a bridge and the downstream bridges are not fully trusted; this prevents a hostile guest from rerouting traffic.
vepa - Data sent between HW ports is sent on the wire to the external switch.
veb - bridging happens in hardware.
This is done by copying the packet per host and changing the multicast destination MAC to a unicast one accordingly.
mcast_to_unicast works on top of the multicast snooping feature of the bridge. Which means unicast copies are only delivered to hosts which are interested in it and signalized this via IGMP/MLD reports previously.
This feature is intended for interface types which have a more reliable and/or efficient way to deliver unicast packets than broadcast ones (e.g. WiFi).
However, it should only be enabled on interfaces where no IGMPv2/MLDv1 report suppression takes place. IGMP/MLD report suppression issue is usually overcome by the network daemon (supplicant) enabling AP isolation and by that separating all STAs.
Delivery of STA-to-STA IP multicast is made possible again by enabling and utilizing the bridge hairpin mode, which considers the incoming port as a potential outgoing port, too (see hairpin option). Hairpin mode is performed after multicast snooping, therefore leading to only deliver reports to STAs running a multicast router.
This command displays port configuration and flags for all bridges.
To display port configuration and flags for a specific bridge, use the "ip link show master <bridge_device>" command.
fdb objects contain known Ethernet addresses on a link.
The corresponding commands display fdb entries, add new entries, append entries, and delete old ones.
This command creates a new fdb entry.
local - is a local permanent fdb entry, which means that the bridge will not forward frames with this destination MAC address and VLAN ID, but terminate them locally. This flag is default unless "static" or "dynamic" are explicitly specified.
permanent - this is a synonym for "local"
static - is a static (no arp) fdb entry
dynamic - is a dynamic reachable age-able fdb entry
self - the operation is fulfilled directly by the driver for the specified network device. If the network device belongs to a master like a bridge, then the bridge is bypassed and not notified of this operation (and if the device does notify the bridge, it is driver-specific behavior and not mandated by this flag, check the driver for more details). The "bridge fdb add" command can also be used on the bridge device itself, and in this case, the added fdb entries will be locally terminated (not forwarded). In the latter case, the "self" flag is mandatory. The flag is set by default if "master" is not specified.
master - if the specified network device is a port that belongs to a master device such as a bridge, the operation is fulfilled by the master device's driver, which may in turn notify the port driver too of the address. If the specified device is a master itself, such as a bridge, this flag is invalid.
router - the destination address is associated with a router. Valid if the referenced device is a VXLAN type device and has route short circuit enabled.
use - the address is in use. User space can use this option to indicate to the kernel that the fdb entry is in use.
extern_learn - this entry was learned externally. This option can be used to indicate to the kernel that an entry was hardware or user-space controller learnt dynamic entry. Kernel will not age such an entry.
sticky - this entry will not change its port due to learning.
The next command line parameters apply only when the specified device
DEV is of type VXLAN.
This command adds a new fdb entry with an already known LLADDR. Valid only for multicast link layer addresses. The command adds support for broadcast and multicast Ethernet MAC addresses. The Ethernet MAC address is added multiple times into the forwarding database and the vxlan device driver sends a copy of the data packet to each entry found.
The arguments are the same as with bridge fdb add.
This command removes an existing fdb entry.
The arguments are the same as with bridge fdb add.
If no matching entry is found, a new one will be created instead.
The arguments are the same as with bridge fdb add.
This command displays the current forwarding table.
With the -statistics option, the command becomes verbose. It prints out the last updated and last used time for each entry.
lookup a bridge forwarding table entry.
flush the matching bridge forwarding table entries. Some options below have a negated form when "no" is prepended to them (e.g. permanent and nopermanent).
mdb objects contain known IP or L2 multicast group addresses on a link.
The corresponding commands display mdb entries, add new entries, and delete old ones.
This command creates a new mdb entry.
permanent - the mdb entry is permanent. Optional for IPv4 and IPv6, mandatory for L2.
temp - the mdb entry is temporary (default)
This command removes an existing mdb entry.
The arguments are the same as with bridge mdb add.
This command displays the current multicast group membership table. The table is populated by IGMP and MLD snooping in the bridge driver automatically. It can be altered by bridge mdb add and bridge mdb del commands manually too.
With the -details option, the command becomes verbose. It prints out the ports known to have a connected router.
With the -statistics option, the command displays timer values for mdb and router port entries.
vlan objects contain known VLAN IDs for a link.
The corresponding commands display vlan filter entries, add new entries, and delete old ones.
This command creates a new vlan filter entry.
This command removes an existing vlan filter entry.
The arguments are the same as with bridge vlan add. The pvid and untagged flags are ignored.
This command changes vlan filter entry's options.
0 - vlan is in STP DISABLED state. Make this vlan completely inactive for STP. This is also called BPDU filter and could be used to disable STP on an untrusted vlan.
1 - vlan is in STP LISTENING state. Only valid if STP is enabled on the bridge. In this state the vlan listens for STP BPDUs and drops all other traffic frames.
2 - vlan is in STP LEARNING state. Only valid if STP is enabled on the bridge. In this state the vlan will accept traffic only for the purpose of updating MAC address tables.
3 - vlan is in STP FORWARDING state. This is the default vlan state.
4 - vlan is in STP BLOCKING state. Only valid if STP is enabled on the bridge. This state is used during the STP election process. In this state, the vlan will only process STP BPDUs.
0 - to disable multicast router.
1 - to let the system detect the presence of routers (default).
2 - to permanently enable multicast traffic forwarding on this vlan and interface.
3 - to temporarily mark this vlan and port as having a multicast router, i.e. enable multicast traffic forwarding. This mode is available only for ports.
This command displays the current VLAN filter table.
With the -details option, the command becomes verbose. It displays the per-vlan options.
With the -statistics option, the command displays per-vlan traffic statistics.
This command displays the current vlan tunnel info mapping.
This command changes vlan filter entry's global options.
This command displays the global VLAN options for each VLAN entry.
vni objects contain known VNI IDs for a dst metadata vxlan link.
The corresponding commands display vni filter entries, add new entries, and delete old ones.
This command creates a new vni filter entry.
This command removes an existing vni filter entry.
The arguments are the same as with bridge vni add.
This command displays the current vni filter table.
With the -statistics option, the command displays per-vni traffic statistics.
The bridge utility can monitor the state of devices and addresses continuously. This option has a slightly different format. Namely, the monitor command is the first in the command line and then the object list follows:
bridge monitor [ all | OBJECT-LIST ]
OBJECT-LIST is the list of object types that we want to monitor. It may contain link, fdb, vlan and mdb. If no file argument is given, bridge opens RTNETLINK, listens on it and dumps state changes in the format described in previous sections.
If a file name is given, it does not listen on RTNETLINK, but opens the file containing RTNETLINK messages saved in binary format and dumps them.
This command uses facilities added in Linux 3.0.
Although the forwarding table is maintained on a per-bridge device basis the bridge device is not part of the syntax. This is a limitation of the underlying netlink neighbour message protocol. When displaying the forwarding table, entries for all bridges are displayed. Add/delete/modify commands determine the underlying bridge device based on the bridge to which the corresponding ethernet device is attached.
ip(8)
Please direct bugreports and patches to: <netdev@vger.kernel.org>
Original Manpage by Stephen Hemminger
| 1 August 2012 | iproute2 |