| .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 " ] [ " |
| .BR nud " { " permanent " | " noarp " | " stale " | " reachable " } ] | " proxy |
| .IR ADDR " } [ " |
| .B dev |
| .IR DEV " ]" |
| |
| .ti -8 |
| .BR "ip neigh" " { " show " | " flush " } [ " proxy " ] [ " to |
| .IR PREFIX " ] [ " |
| .B dev |
| .IR DEV " ] [ " |
| .B nud |
| .IR STATE " ]" |
| |
| |
| .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. |
| |
| .SS ip neighbour add - add a new neighbour entry |
| .SS ip neighbour change - change an existing entry |
| .SS ip neighbour replace - add a new entry or change an existing one |
| |
| 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 lladdr " LLADDRESS" |
| the link layer address of the neighbour. |
| .I LLADDRESS |
| can also be |
| .BR "null" . |
| |
| .TP |
| .BI nud " 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: |
| |
| .in +8 |
| .B permanent |
| - the neighbour entry is valid forever and can be only |
| be removed administratively. |
| .sp |
| |
| .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. |
| .sp |
| |
| .B reachable |
| - the neighbour entry is valid until the reachability |
| timeout expires. |
| .sp |
| |
| .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. |
| .in -8 |
| |
| .SS ip neighbour delete - delete a neighbour entry |
| This command invalidates a neighbour entry. |
| |
| .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. |
| |
| .SS ip neighbour show - list neighbour entries |
| |
| This commands displays neighbour tables. |
| |
| .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 proxy |
| list neighbour proxies. |
| |
| .TP |
| .B unused |
| only list neighbours which are not currently in use. |
| |
| .TP |
| .BI nud " 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" . |
| |
| .SS ip neighbour flush - flush neighbour entries |
| This command flushes neighbour tables, selecting |
| entries to flush by some criteria. |
| |
| .PP |
| 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. |
| |
| .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 |
| |
| .SH SEE ALSO |
| .br |
| .BR ip (8) |
| |
| .SH AUTHOR |
| Original Manpage by Michail Litvak <mci@owl.openwall.com> |
