1.\" $OpenBSD: ndp.8,v 1.46 2019/08/23 15:41:59 kn 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: August 23 2019 $ 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 acnt 40.Op Fl A Ar wait 41.Op Fl d Ar hostname 42.Op Fl f Ar filename 43.Op Fl i Ar interface 44.Op Fl s Ar nodename ether_addr Oo Cm temp Oc Op Cm proxy 45.Op Fl V Ar rdomain 46.Op Ar hostname 47.Sh DESCRIPTION 48The 49.Nm 50command manipulates the address mapping table 51used by the Neighbor Discovery Protocol (NDP). 52.Bl -tag -width Ds 53.It Fl A Ar wait 54Repeat 55.Fl a 56.Pq dump NDP entries 57every 58.Ar wait 59seconds. 60.It Fl a 61Dump the currently existing NDP entries. 62The following information will be printed: 63.Bl -tag -width Ds -offset 3n 64.It Neighbor 65The IPv6 address of the neighbor. 66.It Linklayer Address 67The linklayer address of the neighbor. 68If the address is not available, 69it will be displayed as 70.Dq (incomplete) . 71.It Netif 72The network interface associated with the neighbor cache entry. 73.It Expire 74The time until expiry of the entry. 75If the entry is marked 76.Dq permanent , 77it will never expire. 78.It S 79The state of the neighbor cache entry, as a single letter: 80.Pp 81.Bl -tag -width Ds -offset 3n -compact 82.It D 83Delay 84.It I 85Incomplete 86.It N 87Nostate 88.It P 89Probe 90.It R 91Reachable 92.It S 93Stale 94.It W 95Waitdelete 96.It \&? 97Unknown state (should never happen). 98.El 99.It Flags 100Flags on the neighbor cache entry, in a single letter. 101They are: local 102.Pq Sq l , 103Router 104.Pq Sq R 105and proxy neighbor advertisement 106.Pq Sq p . 107This field may be followed by a decimal number, 108representing the number of NS probes 109the node has sent during the current state. 110.El 111.It Fl c 112Erase all the NDP entries. 113.It Fl d Ar hostname 114Delete the specified NDP entry. 115.It Fl f Ar filename 116Parse entries from 117.Ar file 118to be inserted in the neighbor cache. 119See the 120.Fl s 121option for a description of the file format. 122.It Fl i Ar interface 123View ND information for the specified interface. 124.It Fl n 125Do not perform domain name resolution. 126If a name cannot be resolved without DNS, an error will be reported. 127.It Xo 128.Fl s Ar nodename ether_addr 129.Op Cm temp 130.Op Cm proxy 131.Xc 132Register an NDP entry for the node called nodename with the Ether 133address ether_addr. 134The Ethernet address is given as six hexadecimal bytes separated by 135colons. 136The entry will be permanent unless the word 137.Cm temp 138is given in the command. 139If the word 140.Cm proxy 141is given, this system will act as an ND Proxy server, 142responding to requests for 143.Ar nodename 144even though the node address is not its own. 145.It Fl t 146Print a timestamp on each entry, 147making it possible to merge output with 148.Xr tcpdump 8 . 149Most useful when used with 150.Fl A . 151.It Fl V Ar rdomain 152Select the routing domain. 153.El 154.Sh EXIT STATUS 155.Ex -std ndp 156.Sh SEE ALSO 157.Xr ip6 4 , 158.Xr sysctl.conf 5 , 159.Xr arp 8 , 160.Xr sysctl 8 , 161.Xr tcpdump 8 162.Sh HISTORY 163The 164.Nm 165command first appeared in the WIDE Hydrangea IPv6 protocol stack kit. 166