ip-neighbour.8 (6286B)
- .TH IP\-NEIGHBOUR 8 "20 Dec 2011" "iproute2" "Linux"
- .SH "NAME"
- ip-neighbour \- neighbour/arp tables management.
- .SH "SYNOPSIS"
- .sp
- .ad l
- .in +8
- .ti -8
- .B ip
- .RI "[ " OPTIONS " ]"
- .B neigh
- .RI " { " COMMAND " | "
- .BR help " }"
- .sp
- .ti -8
- .BR "ip neigh" " { " add " | " del " | " change " | " replace " } { "
- .IR ADDR " [ "
- .B lladdr
- .IR LLADDR " ] [ "
- .B nud
- .IR STATE " ] |"
- .B proxy
- .IR ADDR " } [ "
- .B dev
- .IR DEV " ] [ "
- .BR router " ] [ "
- .BR use " ] [ "
- .BR managed " ] [ "
- .BR extern_learn " ]"
- .ti -8
- .BR "ip neigh" " { " show " | " flush " } [ " proxy " ] [ " to
- .IR PREFIX " ] [ "
- .B dev
- .IR DEV " ] [ "
- .B nud
- .IR STATE " ] [ "
- .B vrf
- .IR NAME " ] ["
- .BR nomaster " ]"
- .ti -8
- .B ip neigh get
- .IR ADDR
- .B dev
- .IR DEV
- .ti -8
- .IR STATE " := {"
- .BR permanent " | " noarp " | " stale " | " reachable " | " none " |"
- .BR incomplete " | " delay " | " probe " | " failed " }"
- .SH DESCRIPTION
- The
- .B ip neigh
- command manipulates
- .I neighbour
- objects that establish bindings between protocol addresses and
- link layer addresses for hosts sharing the same link.
- Neighbour entries are organized into tables. The IPv4 neighbour table
- is also known by another name - the ARP table.
- .P
- The corresponding commands display neighbour bindings
- and their properties, add new neighbour entries and delete old ones.
- .TP
- ip neighbour add
- add a new neighbour entry
- .TP
- ip neighbour change
- change an existing entry
- .TP
- ip neighbour replace
- add a new entry or change an existing one
- .RS
- .PP
- These commands create new neighbour records or update existing ones.
- .TP
- .BI to " ADDRESS " (default)
- the protocol address of the neighbour. It is either an IPv4 or IPv6 address.
- .TP
- .BI dev " NAME"
- the interface to which this neighbour is attached.
- .TP
- .BI proxy
- indicates whether we are proxying for this neighbour entry
- .TP
- .BI router
- indicates whether neighbour is a router
- .TP
- .BI use
- this neigh entry is in "use". This option can be used to indicate to
- the kernel that a controller is using this dynamic entry. If the entry
- does not exist, the kernel will resolve it. If it exists, an attempt
- to refresh the neighbor entry will be triggered.
- .TP
- .BI managed
- this neigh entry is "managed". This option can be used to indicate to
- the kernel that a controller is using this dynamic entry. In contrast
- to "use", if the entry does not exist, the kernel will resolve it and
- periodically attempt to auto-refresh the neighbor entry such that it
- remains in resolved state when possible.
- .TP
- .BI extern_learn
- this neigh entry was learned externally. This option can be used to
- indicate to the kernel that this is a controller learnt dynamic entry.
- Kernel will not gc such an entry.
- .TP
- .BI lladdr " LLADDRESS"
- the link layer address of the neighbour.
- .I LLADDRESS
- can also be
- .BR "null" .
- .TP
- .BI nud " STATE"
- the state of the neighbour entry.
- .B nud
- is an abbreviation for 'Neighbour Unreachability Detection'.
- The state can take one of the following values:
- .RS
- .TP
- .B permanent
- the neighbour entry is valid forever and can be only
- be removed administratively.
- .TP
- .B noarp
- the neighbour entry is valid. No attempts to validate
- this entry will be made but it can be removed when its lifetime expires.
- .TP
- .B reachable
- the neighbour entry is valid until the reachability
- timeout expires.
- .TP
- .B stale
- the neighbour entry is valid but suspicious.
- This option to
- .B ip neigh
- does not change the neighbour state if it was valid and the address
- is not changed by this command.
- .TP
- .B none
- this is a pseudo state used when initially creating a neighbour entry or after
- trying to remove it before it becomes free to do so.
- .TP
- .B incomplete
- the neighbour entry has not (yet) been validated/resolved.
- .TP
- .B delay
- neighbor entry validation is currently delayed.
- .TP
- .B probe
- neighbor is being probed.
- .TP
- .B failed
- max number of probes exceeded without success, neighbor validation has
- ultimately failed.
- .RE
- .RE
- .TP
- ip neighbour delete
- delete a neighbour entry
- .RS
- .PP
- The arguments are the same as with
- .BR "ip neigh add" ,
- except that
- .B lladdr
- and
- .B nud
- are ignored.
- .PP
- .B Warning:
- Attempts to delete or manually change a
- .B noarp
- entry created by the kernel may result in unpredictable behaviour.
- Particularly, the kernel may try to resolve this address even
- on a
- .B NOARP
- interface or if the address is multicast or broadcast.
- .RE
- .TP
- ip neighbour show
- list neighbour entries
- .RS
- .TP
- .BI to " ADDRESS " (default)
- the prefix selecting the neighbours to list.
- .TP
- .BI dev " NAME"
- only list the neighbours attached to this device.
- .TP
- .BI vrf " NAME"
- only list the neighbours for given VRF.
- .TP
- .BI nomaster
- only list neighbours attached to an interface with no master.
- .TP
- .BI proxy
- list neighbour proxies.
- .TP
- .B unused
- only list neighbours which are not currently in use.
- .TP
- .BI nud " STATE"
- only list neighbour entries in this state.
- .I NUD_STATE
- takes values listed below or the special value
- .B all
- which means all states. This option may occur more than once.
- If this option is absent,
- .B ip
- lists all entries except for
- .B none
- and
- .BR "noarp" .
- .RE
- .TP
- ip neighbour flush
- flush neighbour entries
- .RS
- This command has the same arguments as
- .B show.
- The differences are that it does not run when no arguments are given,
- and that the default neighbour states to be flushed do not include
- .B permanent
- and
- .BR "noarp" .
- .PP
- With the
- .B -statistics
- option, the command becomes verbose. It prints out the number of
- deleted neighbours and the number of rounds made to flush the
- neighbour table. If the option is given
- twice,
- .B ip neigh flush
- also dumps all the deleted neighbours.
- .RE
- .TP
- ip neigh get
- lookup a neighbour entry to a destination given a device
- .RS
- .TP
- .BI proxy
- indicates whether we should lookup a proxy neighbour entry
- .TP
- .BI to " ADDRESS " (default)
- the prefix selecting the neighbour to query.
- .TP
- .BI dev " NAME"
- get neighbour entry attached to this device.
- .RE
- .SH EXAMPLES
- .PP
- ip neighbour
- .RS
- Shows the current neighbour table in kernel.
- .RE
- .PP
- ip neigh flush dev eth0
- .RS
- Removes entries in the neighbour table on device eth0.
- .RE
- .PP
- ip neigh get 10.0.1.10 dev eth0
- .RS
- Performs a neighbour lookup in the kernel and returns
- a neighbour entry.
- .RE
- .SH SEE ALSO
- .br
- .BR ip (8)
- .SH AUTHOR
- Original Manpage by Michail Litvak <mci@owl.openwall.com>