1.\" $OpenBSD: ndp.8,v 1.40 2016/04/05 18:18:42 jca Exp $ 2.\" $KAME: ndp.8,v 1.28 2002/07/17 08:46:33 itojun Exp $ 3.\" 4.\" Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 5.\" All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the project nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.Dd $Mdocdate: April 5 2016 $ 32.Dt NDP 8 33.Os 34.Sh NAME 35.Nm ndp 36.Nd control/diagnose IPv6 Neighbor Discovery Protocol (NDP) 37.Sh SYNOPSIS 38.Nm ndp 39.Op Fl nrt 40.Op Fl a | c | p 41.Op Fl H | P | R 42.Op Fl A Ar wait 43.Op Fl d Ar hostname 44.Op Fl f Ar filename 45.Op Fl i Ar interface Op Ar flag ... 46.Op Fl s Ar nodename ether_addr Oo Cm temp Oc Op Cm proxy 47.Op Fl V Ar rdomain 48.Op Ar hostname 49.Sh DESCRIPTION 50The 51.Nm 52command manipulates the address mapping table 53used by the Neighbor Discovery Protocol (NDP). 54.Bl -tag -width Ds 55.It Fl A Ar wait 56Repeat 57.Fl a 58.Pq dump NDP entries 59every 60.Ar wait 61seconds. 62.It Fl a 63Dump the currently existing NDP entries. 64The following information will be printed: 65.Bl -tag -width Ds -offset 3n 66.It Neighbor 67The IPv6 address of the neighbor. 68.It Linklayer Address 69The linklayer address of the neighbor. 70If the address is not available, 71it will be displayed as 72.Dq (incomplete) . 73.It Netif 74The network interface associated with the neighbor cache entry. 75.It Expire 76The time until expiry of the entry. 77If the entry is marked 78.Dq permanent , 79it will never expire. 80.It S 81The state of the neighbor cache entry, as a single letter: 82.Pp 83.Bl -tag -width Ds -offset 3n -compact 84.It D 85Delay 86.It I 87Incomplete 88.It N 89Nostate 90.It P 91Probe 92.It R 93Reachable 94.It S 95Stale 96.It W 97Waitdelete 98.It \&? 99Unknown state (should never happen). 100.El 101.It Flags 102Flags on the neighbor cache entry, in a single letter. 103They are: local 104.Pq Sq l , 105Router 106.Pq Sq R 107and proxy neighbor advertisement 108.Pq Sq p . 109This field may be followed by a decimal number, 110representing the number of NS probes 111the node has sent during the current state. 112.El 113.It Fl c 114Erase all the NDP entries. 115.It Fl d Ar hostname 116Delete the specified NDP entry. 117.It Fl f Ar filename 118Parse entries from 119.Ar file 120to be inserted in the neighbor cache. 121See the 122.Fl s 123option for a description of the file format. 124.It Fl H 125Harmonize consistency between the routing table and the default router 126list; install the top entry of the list into the kernel routing table. 127.It Fl i Ar interface Op Ar flag ... 128View ND information for the specified interface. 129If additional arguments are given, 130.Nm 131sets or clears the specified flags for the interface. 132Each flag should be separated by whitespace or tab characters. 133Possible flags are as follows. 134All of the flags can begin with the 135special character 136.Ql - , 137which means the flag should be cleared. 138Note that 139.Fl - 140would be needed before 141.Fl foo 142in this case. 143.Bl -tag -width Ds 144.It Ic nud 145Turn on or off NUD (Neighbor Unreachability Detection) on the 146interface. 147NUD is usually turned on by default. 148.It Ic accept_rtadv 149Specify whether or not to accept Router Advertisement messages 150received on the 151.Ar interface . 152Note that the kernel does not accept Router Advertisement messages 153unless the interface is configured for inet6 autoconfiguration. 154.El 155.It Fl n 156Do not try to resolve numeric addresses to hostnames. 157.It Fl P 158Flush all the entries in the prefix list. 159.It Fl p 160Show the prefix list. 161.It Fl R 162Flush all the entries in the default router list. 163.It Fl r 164Show the default router list. 165.It Xo 166.Fl s Ar nodename ether_addr 167.Op Cm temp 168.Op Cm proxy 169.Xc 170Register an NDP entry for the node called nodename with the Ether 171address ether_addr. 172The Ethernet address is given as six hexadecimal bytes separated by 173colons. 174The entry will be permanent unless the word 175.Cm temp 176is given in the command. 177If the word 178.Cm proxy 179is given, this system will act as an ND Proxy server, 180responding to requests for 181.Ar nodename 182even though the node address is not its own. 183.It Fl t 184Print a timestamp on each entry, 185making it possible to merge output with 186.Xr tcpdump 8 . 187Most useful when used with 188.Fl A . 189.It Fl V Ar rdomain 190Set the routing domain to be used. 191The default is 0. 192.El 193.Sh EXIT STATUS 194.Ex -std ndp 195.Sh SEE ALSO 196.Xr ip6 4 , 197.Xr sysctl.conf 5 , 198.Xr arp 8 , 199.Xr sysctl 8 , 200.Xr tcpdump 8 201.Sh HISTORY 202The 203.Nm 204command first appeared in the WIDE Hydrangea IPv6 protocol stack kit. 205