1.\" $KAME: ndp.8,v 1.28 2002/07/17 08:46:33 itojun Exp $ 2.\" 3.\" Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the project nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" $FreeBSD$ 31.\" 32.Dd May 9, 2014 33.Dt NDP 8 34.Os 35.\" 36.Sh NAME 37.Nm ndp 38.Nd control/diagnose IPv6 neighbor discovery protocol 39.\" 40.Sh SYNOPSIS 41.Nm 42.Op Fl nt 43.Ar hostname 44.Nm 45.Op Fl nt 46.Fl a | c | p 47.Nm 48.Op Fl nt 49.Fl r 50.Nm 51.Op Fl nt 52.Fl H | P | R 53.Nm 54.Op Fl nt 55.Fl A Ar wait 56.Nm 57.Op Fl nt 58.Fl d Ar hostname 59.Nm 60.Op Fl nt 61.Fl f Ar filename 62.Nm 63.Op Fl nt 64.Fl i 65.Ar interface 66.Op Ar expressions ... 67.Nm 68.Op Fl nt 69.Fl I Op Ar interface | Li delete 70.Nm 71.Op Fl nt 72.Fl s Ar nodename etheraddr 73.Op Li temp 74.Op Li proxy 75.\" 76.Sh DESCRIPTION 77The 78.Nm 79utility manipulates the address mapping table 80used by the Neighbor Discovery Protocol (NDP). 81.Bl -tag -width indent 82.It Fl a 83Dump the currently existing NDP entries. 84The following information will be printed: 85.Bl -tag -width "Neighbor" 86.It Neighbor 87IPv6 address of the neighbor. 88.It Linklayer Address 89Linklayer address of the neighbor. 90It could be 91.Dq Li (incomplete) 92when the address is not available. 93.It Netif 94Network interface associated with the neighbor cache entry. 95.It Expire 96The time until expiry of the entry. 97The entry could become 98.Dq Li permanent , 99in which case it will never expire. 100.It S 101State of the neighbor cache entry, as a single letter: 102.Pp 103.Bl -tag -width indent -compact 104.It N 105Nostate 106.It W 107Waitdelete 108.It I 109Incomplete 110.It R 111Reachable 112.It S 113Stale 114.It D 115Delay 116.It P 117Probe 118.It ?\& 119Unknown state (should never happen). 120.El 121.It Flags 122Flags on the neighbor cache entry, in a single letter. 123They are: Router, proxy neighbor advertisement 124.Pq Dq p . 125The field could be followed by a decimal number, 126which means the number of NS probes the node has sent during the current state. 127.El 128.It Fl A Ar wait 129Repeat 130.Fl a 131(dump NDP entries) 132every 133.Ar wait 134seconds. 135.It Fl c 136Erase all the NDP entries. 137.It Fl d 138Delete specified NDP entry. 139.It Fl f Ar filename 140Cause the file 141.Ar filename 142to be read and multiple entries to be set in the 143.Tn NDP 144table. 145Entries 146in the file should be of the form 147.Pp 148.Bd -ragged -offset indent -compact 149.Ar hostname ether_addr 150.Op Cm temp 151.Op Cm proxy 152.Ed 153.Pp 154with argument meanings as given above. 155Leading whitespace and empty lines are ignored. 156A 157.Ql # 158character will mark the rest of the line as a comment. 159.It Fl H 160Harmonize consistency between the routing table and the default router 161list; install the top entry of the list into the kernel routing table. 162.It Fl I 163Shows the default interface used as the default route when 164there is no default router. 165.It Fl I Ar interface 166Specifies the default interface used as the default route when 167there is no default router. 168The 169.Ar interface 170will be used as the default. 171.It Fl I Li delete 172The current default interface will be deleted from the kernel. 173.It Fl i Ar interface Op Ar expressions ... 174View ND information for the specified interface. 175If additional arguments 176.Ar expressions 177are given, 178.Nm 179sets or clears the flags or variables for the interface as specified in 180the expression. 181Each expression should be separated by white spaces or tab characters. 182Possible expressions are as follows. 183Some of the expressions can begin with the 184special character 185.Ql - , 186which means the flag specified in the expression should be cleared. 187Note that you need 188.Fl - 189before 190.Fl foo 191in this case. 192.\" 193.Bl -tag -width indent 194.It Ic nud 195Turn on or off NUD (Neighbor Unreachability Detection) on the 196interface. 197NUD is usually turned on by default. 198.It Ic accept_rtadv 199Specify whether or not to accept Router Advertisement messages 200received on the 201.Ar interface . 202This flag is set by 203.Va net.inet6.ip6.accept_rtadv 204sysctl variable. 205.It Ic auto_linklocal 206Specify whether or not to perform automatic link-local address configuration 207on 208.Ar interface . 209This flag is set by 210.Va net.inet6.ip6.auto_linklocal 211sysctl variable. 212.It Ic no_prefer_iface 213The address on the outgoing interface is preferred by source addess 214selection rule. 215If this flag is set, stop treating the address on the 216.Ar interface 217as special even when the 218.Ar interface 219is outgoing interface. 220The default value of this flag is off. 221.It Ic disabled 222Disable IPv6 operation on the interface. 223When disabled, the interface discards any IPv6 packets 224received on or being sent to the interface. 225In the sending case, an error of ENETDOWN will be returned to the 226application. 227This flag is typically set automatically in the kernel as a result of 228a certain failure of Duplicate Address Detection. 229If the auto_linklocal per-interface flag is set, automatic link-local 230address configuration is performed again when this flag is cleared. 231.It Ic basereachable Ns Li = Ns Pq Ar number 232Specify the BaseReachbleTimer on the interface in millisecond. 233.It Ic retrans Ns Li = Ns Pq Ar number 234Specify the RetransTimer on the interface in millisecond. 235.It Ic curhlim Ns Li = Ns Pq Ar number 236Specify the Cur Hop Limit on the interface. 237.El 238.It Fl n 239Do not try to resolve numeric addresses to hostnames. 240.It Fl p 241Show prefix list. 242The following information will be printed: 243.Bl -tag -width indent 244.It Cm if 245The network interface associated with this prefix. 246.It Cm flags 247The status of the prefix, expressed by a combination of the following 248letters: 249.Pp 250.Bl -tag -width indent -compact 251.It Cm A 252This prefix can be used for stateless address autoconfiguration. 253.It Cm L, Cm O 254This prefix can be used for on-link determination; that is, it can be 255used to determine whether a given destination address is on-link. 256.It Cm D 257There are no reachable routers advertising this prefix. 258.El 259.It Cm vltime 260Valid lifetime; the length of time for which the prefix and a stateless 261autoconfigured address generated from this prefix can be used for the 262source or destination address of a packet. 263.It Cm pltime 264Preferred lifetime; the length of time for which the prefix and a stateless 265autoconfigured address generated from this prefix can be used by upper-layer 266protocols unrestrictedly. 267.It Cm expire 268This is the remaining time that the prefix is in the valid state. 269.It Cm ref 270The number of kernel references held for this prefix. 271.El 272.It Fl P 273Flush all the entries in the prefix list. 274.It Fl r 275Show default router list. 276.It Fl R 277Flush all the entries in the default router list. 278.It Fl s 279Register an NDP entry for a node. 280The entry will be permanent unless the word 281.Li temp 282is given in the command. 283If the word 284.Li proxy 285is given, this system will act as a proxy NDP server, 286responding to requests for 287.Ar hostname 288even though the host address is not its own. 289.It Fl t 290Print timestamp for each entry, 291to make it possible to merge the output with 292.Xr tcpdump 1 . 293Most useful when used with 294.Fl A . 295.El 296.\" 297.Sh EXIT STATUS 298.Ex -std 299.\" 300.Sh SEE ALSO 301.Xr arp 8 302.\" 303.Sh HISTORY 304The 305.Nm 306utility first appeared in the WIDE Hydrangea IPv6 protocol stack kit. 307The 308.Fl I Ar auto_linklocal 309flag first appeared in 310.Fx 8.0 . 311.\" 312.\" .Sh BUGS 313.\" (to be written) 314