ndp(1M)ndp(1M)NAMEndp - 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 specifying
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 inter‐
faces for the host specified by host.
Flushes all Neighbor Discovery cache entries with
IP addresses that are not associated with local inter‐
faces. 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 autonomous. The on-link flag indicates
that addresses with that prefix can be reached
directly without going through a router. The autono‐
mous flag indicates that the prefix came from state‐
less 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 specified "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 file‐
name. Each entry in this file specifies the inter‐
face, 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:
· host (neighbor's host name or IP address)
· hardware address (link layer address) of host
· interface name
· state
· flags
The state of an entry can be or
· An entry is in an state if address resolution is in progress
and the hardware address of the neighbor has not been deter‐
mined.
· An entry is in a state if the neighbor is known to have been
reachable recently.
· 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.
· 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.
· 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
Neighbor Solicitations on this IPv6 address. The temporary flag indi‐
cates 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
anycast flag indicates that the address is an anycast address.
DIAGNOSTICS
returns a non-zero value to indicate errors. A zero return value indi‐
cates 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 inter‐
face:
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 ALSOhosts(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)