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NDP(8) NetBSD System Manager's Manual NDP(8)
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ndp -- control/diagnose IPv6 neighbor discovery protocol
ndp [-nt] hostname
ndp [-nt] -a | -c
ndp [-nt] -A wait
ndp [-nt] -d hostname
ndp [-nt] -f filename
ndp [-nt] -i interface [expressions ...]
ndp [-nt] -s nodename etheraddr [temp] [proxy]
The ndp command manipulates the address mapping table used by the Neigh-
bor Discovery Protocol (NDP).
Repeat -a (dump NDP entries) every wait seconds.
-a Dump the currently existing NDP entries. The following informa-
tion will be printed:
Neighbor IPv6 address of the neighbor.
Linklayer address of the neighbor. It could be
``(incomplete)'' when the address is not available.
Netif Network interface associated with the neighbor cache
Expire The time until expiry of the entry. The entry could
become ``permanent'', in which case it will never
S State of the neighbor cache entry, as a single let-
? Unknown state (should never happen).
Flags Flags on the neighbor cache entry, in a single let-
ter. They are: Router, proxy neighbor advertisement
(``p''). The field could be followed by a decimal
number, which means the number of NS probes the node
has sent during the current state.
-c Erase all the NDP entries.
-d Delete specified NDP entry.
-f Parse the file specified by filename.
-i interface [expressions ...]
View ND information for the specified interface. If additional
arguments expressions are given, ndp sets or clears the flags or
variables for the interface as specified in the expression. Each
expression should be separated by white spaces or tab characters.
Possible expressions are as follows. Some of the expressions can
begin with the special character `-', which means the flag speci-
fied in the expression should be cleared. Note that you need --
before -foo in this case.
nud Turn on or off NUD (Neighbor Unreachability Detection) on
the interface. NUD is usually turned on by default.
Specify whether or not to perform automatic link-local
address configuration on interface. This flag is set by
net.inet6.ip6.auto_linklocal sysctl variable.
Prefer addresses on the interface as candidates of the
source address for outgoing packets. The default value
of this flag is off. For more details about the entire
algorithm of source address selection, see the
IMPLEMENTATION file supplied with the KAME kit.
Disable IPv6 operation on the interface. When disabled,
the interface discards any IPv6 packets received on or
being sent to the interface and any IPv6 addresses on the
interface are marked as ``tentative''. When the disabled
flag is cleared, DAD will be performed. In the sending
case, an error of ENETDOWN will be returned to the appli-
cation. This flag is typically set automatically in the
kernel as a result of a certain failure of Duplicate
Address Detection. While the flag can be set or cleared
by hand with the ndp command, it is not generally advis-
able to modify this flag manually.
Specify the BaseReachbleTimer on the interface in mil-
Specify the RetransTimer on the interface in millisecond.
Specify the Cur Hop Limit on the interface.
-n Do not try to resolve numeric addresses to hostnames.
-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 a proxy NDP server, responding
to requests for hostname even though the host address is not its
-t Print timestamp on each entry, making it possible to merge output
with tcpdump(8). Most useful when used with -A.
The ndp command will exit with 0 on success, and non-zero on errors.
The ndp command first appeared in the WIDE Hydrangea IPv6 protocol stack
NetBSD 9.99 September 15, 2020 NetBSD 9.99
Modified for NetBSD
by Kimmo Suominen