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.Dd May 9, 2014 31.Dt NDP 8 32.Os 33.\" 34.Sh NAME 35.Nm ndp 36.Nd control/diagnose IPv6 neighbor discovery protocol 37.\" 38.Sh SYNOPSIS 39.Nm 40.Op Fl nt 41.Ar hostname 42.Nm 43.Op Fl nt 44.Fl a | c | p 45.Nm 46.Op Fl nt 47.Fl r 48.Nm 49.Op Fl nt 50.Fl H | P | R 51.Nm 52.Op Fl nt 53.Fl A Ar wait 54.Nm 55.Op Fl nt 56.Fl d Ar hostname 57.Nm 58.Op Fl nt 59.Fl f Ar filename 60.Nm 61.Op Fl nt 62.Fl i 63.Ar interface 64.Op Ar expressions ... 65.Nm 66.Op Fl nt 67.Fl I Op Ar interface | Li delete 68.Nm 69.Op Fl nt 70.Fl s Ar nodename etheraddr 71.Op Li temp 72.Op Li proxy 73.\" 74.Sh DESCRIPTION 75The 76.Nm 77utility manipulates the address mapping table 78used by the Neighbor Discovery Protocol (NDP). 79.Bl -tag -width indent 80.It Fl a 81Dump the currently existing NDP entries. 82The following information will be printed: 83.Bl -tag -width "Neighbor" 84.It Neighbor 85IPv6 address of the neighbor. 86.It Linklayer Address 87Linklayer address of the neighbor. 88It could be 89.Dq Li (incomplete) 90when the address is not available. 91.It Netif 92Network interface associated with the neighbor cache entry. 93.It Expire 94The time until expiry of the entry. 95The entry could become 96.Dq Li permanent , 97in which case it will never expire. 98.It S 99State of the neighbor cache entry, as a single letter: 100.Pp 101.Bl -tag -width indent -compact 102.It N 103Nostate 104.It W 105Waitdelete 106.It I 107Incomplete 108.It R 109Reachable 110.It S 111Stale 112.It D 113Delay 114.It P 115Probe 116.It ?\& 117Unknown state (should never happen). 118.El 119.It Flags 120Flags on the neighbor cache entry, in a single letter. 121They are: Router, proxy neighbor advertisement 122.Pq Dq p . 123The field could be followed by a decimal number, 124which means the number of NS probes the node has sent during the current state. 125.El 126.It Fl A Ar wait 127Repeat 128.Fl a 129(dump NDP entries) 130every 131.Ar wait 132seconds. 133.It Fl c 134Erase all the NDP entries. 135.It Fl d 136Delete specified NDP entry. 137.It Fl f Ar filename 138Cause the file 139.Ar filename 140to be read and multiple entries to be set in the 141.Tn NDP 142table. 143Entries 144in the file should be of the form 145.Pp 146.Bd -ragged -offset indent -compact 147.Ar hostname ether_addr 148.Op Cm temp 149.Op Cm proxy 150.Ed 151.Pp 152with argument meanings as given above. 153Leading whitespace and empty lines are ignored. 154A 155.Ql # 156character will mark the rest of the line as a comment. 157.It Fl H 158Harmonize consistency between the routing table and the default router 159list; install the top entry of the list into the kernel routing table. 160.It Fl I 161Shows the default interface used as the default route when 162there is no default router. 163.It Fl I Ar interface 164Specifies the default interface used as the default route when 165there is no default router. 166The 167.Ar interface 168will be used as the default. 169.It Fl I Li delete 170The current default interface will be deleted from the kernel. 171.It Fl i Ar interface Op Ar expressions ... 172View ND information for the specified interface. 173If additional arguments 174.Ar expressions 175are given, 176.Nm 177sets or clears the flags or variables for the interface as specified in 178the expression. 179Each expression should be separated by white spaces or tab characters. 180Possible expressions are as follows. 181Some of the expressions can begin with the 182special character 183.Ql - , 184which means the flag specified in the expression should be cleared. 185Note that you need 186.Fl - 187before 188.Fl foo 189in this case. 190.\" 191.Bl -tag -width indent 192.It Ic nud 193Turn on or off NUD (Neighbor Unreachability Detection) on the 194interface. 195NUD is usually turned on by default. 196.It Ic accept_rtadv 197Specify whether or not to accept Router Advertisement messages 198received on the 199.Ar interface . 200This flag is set by 201.Va net.inet6.ip6.accept_rtadv 202sysctl variable. 203.It Ic auto_linklocal 204Specify whether or not to perform automatic link-local address configuration 205on 206.Ar interface . 207This flag is set by 208.Va net.inet6.ip6.auto_linklocal 209sysctl variable. 210.It Ic no_prefer_iface 211The address on the outgoing interface is preferred by source addess 212selection rule. 213If this flag is set, stop treating the address on the 214.Ar interface 215as special even when the 216.Ar interface 217is outgoing interface. 218The default value of this flag is off. 219.It Ic disabled 220Disable IPv6 operation on the interface. 221When disabled, the interface discards any IPv6 packets 222received on or being sent to the interface. 223In the sending case, an error of ENETDOWN will be returned to the 224application. 225This flag is typically set automatically in the kernel as a result of 226a certain failure of Duplicate Address Detection. 227If the auto_linklocal per-interface flag is set, automatic link-local 228address configuration is performed again when this flag is cleared. 229.It Ic basereachable Ns Li = Ns Pq Ar number 230Specify the BaseReachbleTimer on the interface in millisecond. 231.It Ic retrans Ns Li = Ns Pq Ar number 232Specify the RetransTimer on the interface in millisecond. 233.It Ic curhlim Ns Li = Ns Pq Ar number 234Specify the Cur Hop Limit on the interface. 235.El 236.It Fl n 237Do not try to resolve numeric addresses to hostnames. 238.It Fl p 239Show prefix list. 240The following information will be printed: 241.Bl -tag -width indent 242.It Cm if 243The network interface associated with this prefix. 244.It Cm flags 245The status of the prefix, expressed by a combination of the following 246letters: 247.Pp 248.Bl -tag -width indent -compact 249.It Cm A 250This prefix can be used for stateless address autoconfiguration. 251.It Cm L, Cm O 252This prefix can be used for on-link determination; that is, it can be 253used to determine whether a given destination address is on-link. 254.It Cm D 255There are no reachable routers advertising this prefix. 256.El 257.It Cm vltime 258Valid lifetime; the length of time for which the prefix and a stateless 259autoconfigured address generated from this prefix can be used for the 260source or destination address of a packet. 261.It Cm pltime 262Preferred lifetime; the length of time for which the prefix and a stateless 263autoconfigured address generated from this prefix can be used by upper-layer 264protocols unrestrictedly. 265.It Cm expire 266This is the remaining time that the prefix is in the valid state. 267.It Cm ref 268The number of kernel references held for this prefix. 269.El 270.It Fl P 271Flush all the entries in the prefix list. 272.It Fl r 273Show default router list. 274.It Fl R 275Flush all the entries in the default router list. 276.It Fl s 277Register an NDP entry for a node. 278The entry will be permanent unless the word 279.Li temp 280is given in the command. 281If the word 282.Li proxy 283is given, this system will act as a proxy NDP server, 284responding to requests for 285.Ar hostname 286even though the host address is not its own. 287.It Fl t 288Print timestamp for each entry, 289to make it possible to merge the output with 290.Xr tcpdump 1 . 291Most useful when used with 292.Fl A . 293.El 294.\" 295.Sh EXIT STATUS 296.Ex -std 297.\" 298.Sh SEE ALSO 299.Xr arp 8 300.\" 301.Sh HISTORY 302The 303.Nm 304utility first appeared in the WIDE Hydrangea IPv6 protocol stack kit. 305The 306.Fl I Ar auto_linklocal 307flag first appeared in 308.Fx 8.0 . 309.\" 310.\" .Sh BUGS 311.\" (to be written) 312