1.\" $OpenBSD: ndp.8,v 1.32 2014/07/12 17:03:47 henning 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: July 12 2014 $ 32.Dt NDP 8 33.Os 34.\" 35.Sh NAME 36.Nm ndp 37.Nd control/diagnose IPv6 Neighbor Discovery Protocol (NDP) 38.\" 39.Sh SYNOPSIS 40.Nm ndp 41.Bk -words 42.Op Fl nrt 43.Op Fl a | c | p 44.Op Fl H | P | R 45.Op Fl A Ar wait 46.Op Fl d Ar hostname 47.Op Fl f Ar filename 48.Op Fl i Ar interface Op Ar flag ... 49.Op Fl s Ar nodename etheraddr Oo Ic temp Oc Op Ic proxy 50.Op Fl V Ar rdomain 51.Op Ar hostname 52.Ek 53.\" 54.Sh DESCRIPTION 55The 56.Nm 57command manipulates the address mapping table 58used by the Neighbor Discovery Protocol (NDP). 59.Bl -tag -width Ds 60.It Fl A Ar wait 61Repeat 62.Fl a 63.Pq dump NDP entries 64every 65.Ar wait 66seconds. 67.It Fl a 68Dump the currently existing NDP entries. 69The following information will be printed: 70.Bl -tag -width Ds -offset 3n 71.It Neighbor 72The IPv6 address of the neighbor. 73.It Linklayer Address 74The linklayer address of the neighbor. 75If the address is not available, 76it will be displayed as 77.Dq (incomplete) . 78.It Netif 79The network interface associated with the neighbor cache entry. 80.It Expire 81The time until expiry of the entry. 82If the entry is marked 83.Dq permanent , 84it will never expire. 85.It S 86The state of the neighbor cache entry, as a single letter: 87.Pp 88.Bl -tag -width Ds -offset 3n -compact 89.It D 90Delay 91.It I 92Incomplete 93.It N 94Nostate 95.It P 96Probe 97.It R 98Reachable 99.It S 100Stale 101.It W 102Waitdelete 103.It \&? 104Unknown state (should never happen). 105.El 106.It Flags 107Flags on the neighbor cache entry, in a single letter. 108They are: Router 109.Pq Sq R 110and proxy neighbor advertisement 111.Pq Sq p . 112This field may be followed by a decimal number, 113representing the number of NS probes 114the node has sent during the current state. 115.El 116.It Fl c 117Erase all the NDP entries. 118.It Fl d Ar hostname 119Delete the specified NDP entry. 120.It Fl f Ar filename 121Parse the file specified by 122.Ar filename . 123.It Fl H 124Harmonize consistency between the routing table and the default router 125list; install the top entry of the list into the kernel routing table. 126.It Fl i Ar interface Op Ar flag ... 127View ND information for the specified interface. 128If additional arguments are given, 129.Nm 130sets or clears the specified flags for the interface. 131Each flag should be separated by whitespace or tab characters. 132Possible flags are as follows. 133All of the flags can begin with the 134special character 135.Ql - , 136which means the flag should be cleared. 137Note that 138.Fl - 139would be needed before 140.Fl foo 141in this case. 142.\" 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 autconfiguration. 154.\".It Xo 155.\".Ic prefer_source 156.\".Xc 157.\"Prefer addresses on the 158.\".Ar interface 159.\"as candidates of the source address for outgoing packets. 160.\"The default value of this flag is off. 161.\"For more details about the entire algorithm of source address 162.\"selection, see the 163.\".Pa IMPLEMENTATION 164.\"file supplied with the KAME kit. 165.El 166.It Fl n 167Do not try to resolve numeric addresses to hostnames. 168.It Fl P 169Flush all the entries in the prefix list. 170.It Fl p 171Show the prefix list. 172.It Fl R 173Flush all the entries in the default router list. 174.It Fl r 175Show the default router list. 176.It Xo 177.Fl s Ar nodename etheraddr 178.Op Cm temp 179.Op Cm proxy 180.Xc 181Register an NDP entry for a node. 182The entry will be permanent unless the word 183.Cm temp 184is given in the command. 185If the word 186.Cm proxy 187is given, this system will act as a proxy NDP server, 188responding to requests for 189.Ar hostname 190even though the host address is not its own. 191.It Fl t 192Print a timestamp on each entry, 193making it possible to merge output with 194.Xr tcpdump 8 . 195Most useful when used with 196.Fl A . 197.It Fl V Ar rdomain 198Set the routing domain to be used. 199The default is 0. 200.El 201.Sh EXIT STATUS 202.Ex -std ndp 203.\" 204.Sh SEE ALSO 205.Xr ip6 4 , 206.Xr sysctl.conf 5 , 207.Xr arp 8 , 208.Xr sysctl 8 , 209.Xr tcpdump 8 210.\" 211.Sh HISTORY 212The 213.Nm 214command first appeared in the WIDE Hydrangea IPv6 protocol stack kit. 215.\" 216.\" .Sh BUGS 217.\" (to be written) 218