NDP(8) BSD System Manager's Manual NDP(8)NAME
ndp -- control/diagnose IPv6 neighbor discovery protocol
SYNOPSIS
ndp -a [-lnt]
ndp -A wait [-nt]
ndp -c [-nt]
ndp -d [-nt] hostname
ndp -f [-nt] filename
ndp -H
ndp -I [delete | interface]
ndp -i interface [flags...]
ndp -p
ndp -P
ndp -r
ndp -R
ndp -s [-nt] nodename ether_addr [temp] [proxy]
DESCRIPTION
The ndp command manipulates the address mapping table used by Neighbor Discovery Protocol (NDP).
-a Dump the currently existing NDP entries.
-A wait
Repeat -a (dump NDP entries) every wait seconds.
-c Erase all the NDP entries.
-d Delete specified NDP entry.
-f Parse the file specified by filename.
-H Harmonize consistency between the routing table and the default router list; install the top entry of the list into the kernel rout-
ing table.
-I [delete | interface]
Shows or specifies the default interface used as the default route when there is no default router. If no argument is given to the
option, the current default interface will be shown. If an interface is specified, the interface will be used as the default. If a
special keyword delete is specified, the current default interface will be deleted from the kernel.
-i interface [flags...]
View ND information for the specified interface. If additional arguments flags are given, ndp sets or clears the specified flags for
the interface. Possible flags are as follows. All of the flags can begin with the special character '-', which means the flag
should be cleared.
nud turn on or off NUD (Neighbor Unreachability Detection) on the interface. NUD is usually turned on by default.
disabled
IPv6 can be disabled separately from other network protocols. This flag can be turned on automatically when Duplicate Address
Detection (DAD) indicates that another device on the network is using the same link-local address.
proxy_prefixes
the interface is enabled to proxy neighbor discovery for global scope prefixes matching those on link at other interfaces.
ignore_na
ignore neighbor advertisements received on this interface.
insecure do not use cryptographically generated addresses (CGA) on this interface.
-l Show link-layer reachability information.
-n Do not try to resolve numeric address to hostname.
-p Show prefix list.
-P Flush all the entries in the prefix list.
-r Show default router list.
-R Flush all the entries in the default router list.
-s Register an NDP entry for a node. The entry will be permanent unless the word temp is given in the command. If the word proxy is
given, this system will act as an proxy NDP server, responding to requests for hostname even though the host address is not its own.
-t Print timestamp on each entries, to make it possible to merge output with tcpdump(1). Most useful when used with -A.
-x Show extended link-layer reachability information in addition to that shown by the -l flag.
-w Show the cryptographically generated address (CGA) parameters for the node.
RETURN VALUES
The ndp command will exit with 0 on success, and non-zero on errors.
SEE ALSO arp(8)HISTORY
The ndp command first appeared in WIDE Hydrangea IPv6 protocol stack kit.
BSD May 17, 1998 BSD
Check Out this Related Man Page
ndp(1M)ndp(1M)NAME
ndp - IPv6 Neighbor Discovery cache display and control
SYNOPSIS
host
interface]
interface] interval
interface] host
interface]
interface]
interface]
interface host hw_addr
filename
DESCRIPTION
The command displays and modifies the IPv6 Neighbor Discovery cache as specified in the IPv6 Neighbor Discovery (ND) protocol.
Options
recognizes the following options and arguments:
host Display the current Neighbor Discovery cache entries for the host specified by host, which is either a name present in the
hostname database (see hosts(4)), or an IPv6 address expressed in colon notation (see inet6(3N)).
Select the Neighbor Discovery cache entries for the specified
interface. There is no distinction between primary and secondary interfaces. Therefore, specifying is the same as speci-
fying
Display host addresses in IPv6 colon notation.
If this option is not specified, attempts to display host addresses symbolically first, and falls back to displaying the
host addresses in IPv6 colon notation if that failed.
Display all Neighbor Discovery cache entries.
Continuously display all Neighbor Discovery cache entries,
updated at each interval, measured in seconds.
Deletes Neighbor Discovery cache entries with
IP addresses that are not associated with local interfaces for the host specified by host.
Flushes all Neighbor Discovery cache entries with
IP addresses that are not associated with local interfaces. These are entries with the (local) flag set. Refer to the
section of this manpage for information about flags.
(Quiet) Do not write anything to standard output.
This option only applies to and options.
Display the prefix list in the Neighbor Discovery cache table.
The prefix list defines a set of IP address ranges that the host can reach. The prefix flags are for on-link, and for au-
tonomous. The on-link flag indicates that addresses with that prefix can be reached directly without going through a
router. The autonomous flag indicates that the prefix came from stateless autoconfiguration.
Flushes all autoconfigured addresses learned from prefixes
advertised by the Router Advertisement Messages.
Create a Neighbor Discovery cache entry for the
interface specified by interface, the host specified by host, and the hardware address (link-layer address) specified by
hw_addr. The hw_addr is specified as where each x is a hexadecimal digit.
If is specified, the entry is published, which means that this system will respond to Neighbor Solicitation for the speci-
fied "host" even though the host address is not its own. If is specified, it means that the published entry refers to an
anycast address. This parameter can only be specified when the parameter is specified.
Create Neighbor Discovery cache entries from the
specifications found in the file specified by filename. Each entry in this file specifies the interface, host, hw_addr,
and optionally the flag. For example, the content of this file can be:
The use of and options requires root privileges.
Contents
A Neighbor Discovery cache entry includes the following fields:
o host (neighbor's host name or IP address)
o hardware address (link layer address) of host
o interface name
o state
o flags
The state of an entry can be or
o An entry is in an state if address resolution is in progress and the hardware address of the neighbor has not been determined.
o An entry is in a state if the neighbor is known to have been reachable recently.
o An entry is in a state if the neighbor is no longer known to be reachable. However, no attempt has been made to verify its
reachability because no traffic has been sent to this neighbor.
o An entry is in a state if the neighbor is no longer known to be reachable, and traffic has recently been sent to the neighbor.
o An entry is in a state if the neighbor is no longer known to be reachable, and unicast Neighbor Solicitation probes have been
sent to verify reachability.
The flags can be (Deprecated), (Local), (Published), (Temporary), (Auto), or (anycast). A deprecated address can be used for receiving
packets, but it should not be used for sending packets because its validity is expected to expire soon. The local flag indicates that this
Neighbor Discovery cache entry corresponds to an interface on this host. The published flag indicates that the host will respond to Neigh-
bor Solicitations on this IPv6 address. The temporary flag indicates that the address has a randomly generated interface identifier which
changes over time. The autonomous flag indicates that the prefix for the address came from stateless address autoconfiguration. The any-
cast flag indicates that the address is an anycast address.
DIAGNOSTICS
returns a non-zero value to indicate errors. A zero return value indicates success.
EXAMPLES
The following output shows the local interfaces and the IP addresses assigned to them.
Name Mtu Address/Prefix Ipkts Opkts
lan1 1500 fe80::210:83ff:fef7:3a21/10 982 759
lan1:1 1500 fec0::9:210:83ff:fef7:3a21/64 0 0
lan3 1500 fe80::210:83ff:fef7:7a9d/10 0 0
lo0 4136 ::1/128 57 57
To display the entire Neighbor Discovery cache:
Destination Physical Address Interface State Flags
fe80::202:fdff:fe36:8720 0:2:fd:36:87:20 lan1 STALE -
fec0::9:210:83ff:fef7:3a21 0:10:83:f7:3a:21 lan1:1 REACHABLE LP
fe80::210:83ff:fef7:3a21 0:10:83:f7:3a:21 lan1 REACHABLE LP
fe80::210:83ff:fef7:7a9d 0:10:83:f7:7a:9d lan3 REACHABLE LP
To show Neighbor Discovery cache entries for a host:
Destination Physical Address Interface State Flags
fe80::210:83ff:fef7:3a21 0:10:83:f7:3a:21 lan1 REACHABLE LP
To show Neighbor Discovery cache entries for an interface:
Destination Physical Address Interface State Flags
fe80::210:83ff:fef7:7a9d 0:10:83:f7:7a:9d lan3 REACHABLE LP
To delete a Neighbor Discovery cache entries for a host and an interface:
fe80::202:fdff:fe36:8720 (fe80::202:fdff:fe36:8720) deleted.
To show the prefix list:
Prefix List Interface Valid Preferred Flags
Entries Lifetime Lifetime
fec0:0:0:9::/64 lan1 167 107 A
fe80::/10 lan1 inf inf LA
fe80::/10 lan3 inf inf LA
To add an entry in the Neighbor Discovery cache:
nodeb (2001::1) added.
Destination Physical Address Interface State Flags
fe80::210:83ff:fef7:7a9d 0:10:83:f7:7a:9d lan3 REACHABLE LP
2001::1 0:1:2:3:4:5 lan3 - -
To flush all remote entries:
nodea (fe80::202:fdff:fe36:8720) flushed.
nodeb (2001::1) flushed.
AUTHOR
was developed by HP.
SEE ALSO hosts(4), inet6(3N), ndp(7P).
Neighbor Discovery for IP Version 6 (IPv6), RFC2461, Narten, Nordmark, Simpson.
IPv6 Stateless Address Autoconfiguration, RFC2462, Thomson, Narten.
ndp(1M)