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 Jan 10, 2013 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 140Parse the file specified by 141.Ar filename . 142.It Fl H 143Harmonize consistency between the routing table and the default router 144list; install the top entry of the list into the kernel routing table. 145.It Fl I 146Shows the default interface used as the default route when 147there is no default router. 148.It Fl I Ar interface 149Specifies the default interface used as the default route when 150there is no default router. 151The 152.Ar interface 153will be used as the default. 154.It Fl I Li delete 155The current default interface will be deleted from the kernel. 156.It Fl i Ar interface Op Ar expressions ... 157View ND information for the specified interface. 158If additional arguments 159.Ar expressions 160are given, 161.Nm 162sets or clears the flags or variables for the interface as specified in 163the expression. 164Each expression should be separated by white spaces or tab characters. 165Possible expressions are as follows. 166Some of the expressions can begin with the 167special character 168.Ql - , 169which means the flag specified in the expression should be cleared. 170Note that you need 171.Fl - 172before 173.Fl foo 174in this case. 175.\" 176.Bl -tag -width indent 177.It Ic nud 178Turn on or off NUD (Neighbor Unreachability Detection) on the 179interface. 180NUD is usually turned on by default. 181.It Ic accept_rtadv 182Specify whether or not to accept Router Advertisement messages 183received on the 184.Ar interface . 185This flag is set by 186.Va net.inet6.ip6.accept_rtadv 187sysctl variable. 188.It Ic auto_linklocal 189Specify whether or not to perform automatic link-local address configuration 190on 191.Ar interface . 192This flag is set by 193.Va net.inet6.ip6.auto_linklocal 194sysctl variable. 195.It Ic no_prefer_iface 196The address on the outgoing interface is preferred by source addess 197selection rule. 198If this flag is set, stop treating the address on the 199.Ar interface 200as special even when the 201.Ar interface 202is outgoing interface. 203The default value of this flag is off. 204.It Ic disabled 205Disable IPv6 operation on the interface. 206When disabled, the interface discards any IPv6 packets 207received on or being sent to the interface. 208In the sending case, an error of ENETDOWN will be returned to the 209application. 210This flag is typically set automatically in the kernel as a result of 211a certain failure of Duplicate Address Detection. 212If the auto_linklocal per-interface flag is set, automatic link-local 213address configuration is performed again when this flag is cleared. 214.It Ic basereachable Ns Li = Ns Pq Ar number 215Specify the BaseReachbleTimer on the interface in millisecond. 216.It Ic retrans Ns Li = Ns Pq Ar number 217Specify the RetransTimer on the interface in millisecond. 218.It Ic curhlim Ns Li = Ns Pq Ar number 219Specify the Cur Hop Limit on the interface. 220.El 221.It Fl n 222Do not try to resolve numeric addresses to hostnames. 223.It Fl p 224Show prefix list. 225The following information will be printed: 226.Bl -tag -width indent 227.It Cm if 228The network interface associated with this prefix. 229.It Cm flags 230The status of the prefix, expressed by a combination of the following 231letters: 232.Pp 233.Bl -tag -width indent -compact 234.It Cm A 235This prefix can be used for stateless address autoconfiguration. 236.It Cm L, Cm O 237This prefix can be used for on-link determination; that is, it can be 238used to determine whether a given destination address is on-link. 239.It Cm D 240There are no reachable routers advertising this prefix. 241.El 242.It Cm vltime 243Valid lifetime; the length of time for which the prefix and a stateless 244autoconfigured address generated from this prefix can be used for the 245source or destination address of a packet. 246.It Cm pltime 247Preferred lifetime; the length of time for which the prefix and a stateless 248autoconfigured address generated from this prefix can be used by upper-layer 249protocols unrestrictedly. 250.It Cm expire 251This is the remaining time that the prefix is in the valid state. 252.It Cm ref 253The number of kernel references held for this prefix. 254.El 255.It Fl P 256Flush all the entries in the prefix list. 257.It Fl r 258Show default router list. 259.It Fl R 260Flush all the entries in the default router list. 261.It Fl s 262Register an NDP entry for a node. 263The entry will be permanent unless the word 264.Li temp 265is given in the command. 266If the word 267.Li proxy 268is given, this system will act as a proxy NDP server, 269responding to requests for 270.Ar hostname 271even though the host address is not its own. 272.It Fl t 273Print timestamp for each entry, 274to make it possible to merge the output with 275.Xr tcpdump 1 . 276Most useful when used with 277.Fl A . 278.El 279.\" 280.Sh EXIT STATUS 281.Ex -std 282.\" 283.Sh SEE ALSO 284.Xr arp 8 285.\" 286.Sh HISTORY 287The 288.Nm 289utility first appeared in the WIDE Hydrangea IPv6 protocol stack kit. 290The 291.Fl I Ar auto_linklocal 292flag first appeared in 293.Fx 8.0 . 294.\" 295.\" .Sh BUGS 296.\" (to be written) 297