1.\" $NetBSD: ndp.8,v 1.23 2009/03/11 18:52:54 joerg Exp $ 2.\" $KAME: ndp.8,v 1.33 2005/10/19 14:57:42 suz 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 March 5, 2006 32.Dt NDP 8 33.Os 34.\" 35.Sh NAME 36.Nm ndp 37.Nd control/diagnose IPv6 neighbor discovery protocol 38.\" 39.Sh SYNOPSIS 40.Nm ndp 41.Op Fl nt 42.Ar hostname 43.Nm ndp 44.Op Fl nt 45.Fl a | Fl c | Fl p 46.Nm ndp 47.Op Fl nt 48.Fl r 49.Nm ndp 50.Op Fl nt 51.Fl H | Fl P | Fl R 52.Nm ndp 53.Op Fl nt 54.Fl A Ar wait 55.Nm ndp 56.Op Fl nt 57.Fl d Ar hostname 58.Nm ndp 59.Op Fl nt 60.Fl f Ar filename 61.Nm ndp 62.Op Fl nt 63.Fl i 64.Ar interface 65.Op Ar expressions ... 66.Nm ndp 67.Op Fl nt 68.Fl I Op Ar interface | Li delete 69.Nm ndp 70.Op Fl nt 71.Fl s Ar nodename etheraddr 72.Op Li temp 73.Op Li proxy 74.\" 75.Sh DESCRIPTION 76The 77.Nm 78command manipulates the address mapping table 79used by the Neighbor Discovery Protocol (NDP). 80.Bl -tag -width Ds 81.It Fl a 82Dump the currently existing NDP entries. 83The following information will be printed: 84.Bl -tag -width NeighborXX 85.It Neighbor 86IPv6 address of the neighbor. 87.It Linklayer Address 88Linklayer address of the neighbor. 89It could be 90.Dq Li (incomplete) 91when the address is not available. 92.It Netif 93Network interface associated with the neighbor cache entry. 94.It Expire 95The time until expiry of the entry. 96The entry could become 97.Dq Li permanent , 98in which case it will never expire. 99.It S 100State of the neighbor cache entry, as a single letter: 101.Pp 102.Bl -tag -width indent -compact 103.It N 104Nostate 105.It W 106Waitdelete 107.It I 108Incomplete 109.It R 110Reachable 111.It S 112Stale 113.It D 114Delay 115.It P 116Probe 117.It ? 118Unknown state (should never happen). 119.El 120.It Flags 121Flags on the neighbor cache entry, in a single letter. 122They are: Router, proxy neighbor advertisement 123.Pq Dq p . 124The field could be followed by a decimal number, 125which means the number of NS probes the node has sent during the current state. 126.El 127.It Fl A Ar wait 128Repeat 129.Fl a 130.Pq dump NDP entries 131every 132.Ar wait 133seconds. 134.It Fl c 135Erase all the NDP entries. 136.It Fl d 137Delete specified NDP entry. 138.It Fl f 139Parse the file specified by 140.Ar filename . 141.It Fl H 142Harmonize consistency between the routing table and the default router 143list; install the top entry of the list into the kernel routing table. 144.It Fl I 145Shows the default interface used as the default route when 146there is no default router. 147.It Fl I Ar interface 148Specifies the default 149.Ar interface 150to be used when there is no interface specified even though required. 151.It Fl I Li delete 152The current default interface will be deleted from the kernel. 153.It Fl i Ar interface Op Ar expressions ... 154View ND information for the specified interface. 155If additional arguments 156.Ar expressions 157are given, 158.Nm 159sets or clears the flags or variables for the interface as specified in 160the expression. 161Each expression should be separated by white spaces or tab characters. 162Possible expressions are as follows. 163Some of the expressions can begin with the 164special character 165.Ql - , 166which means the flag specified in the expression should be cleared. 167Note that you need 168.Fl - 169before 170.Fl foo 171in this case. 172.\" 173.Pp 174.Bl -tag -width Ds -compact 175.It Ic nud 176Turn on or off NUD (Neighbor Unreachability Detection) on the 177interface. 178NUD is usually turned on by default. 179.It Ic accept_rtadv 180Specify whether or not to accept Router Advertisement messages 181received on the 182.Ar interface . 183Note that the kernel does not accept Router Advertisement messages 184unless the 185.Li net.inet6.ip6.accept_rtadv 186variable is non-0, even if the flag is on. 187This flag is set to 1 by default. 188.It Ic prefer_source 189Prefer addresses on the 190.Ar interface 191as candidates of the source address for outgoing packets. 192The default value of this flag is off. 193For more details about the entire algorithm of source address 194selection, see the 195.Pa IMPLEMENTATION 196file supplied with the KAME kit. 197.It Ic disabled 198Disable IPv6 operation on the interface. 199When disabled, the interface discards any IPv6 packets 200received on or being sent to the interface. 201In the sending case, an error of ENETDOWN will be returned to the 202application. 203This flag is typically set automatically in the kernel as a result of 204a certain failure of Duplicate Address Detection. 205While the flag can be set or cleared by hand with the 206.Nm 207command, it is not generally advisable to modify this flag manually. 208.It Ic basereachable=(number) 209Specify the BaseReachbleTimer on the interface in millisecond. 210.It Ic retrans=(number) 211Specify the RetransTimer on the interface in millisecond. 212.It Ic curhlim=(number) 213Specify the Cur Hop Limit on the interface. 214.El 215.It Fl n 216Do not try to resolve numeric addresses to hostnames. 217.It Fl p 218Show prefix list. 219.It Fl P 220Flush all the entries in the prefix list. 221.It Fl r 222Show default router list. 223.It Fl R 224Flush all the entries in the default router list. 225.It Fl s 226Register an NDP entry for a node. 227The entry will be permanent unless the word 228.Li temp 229is given in the command. 230If the word 231.Li proxy 232is given, this system will act as a proxy NDP server, 233responding to requests for 234.Ar hostname 235even though the host address is not its own. 236.It Fl t 237Print timestamp on each entry, 238making it possible to merge output with 239.Xr tcpdump 8 . 240Most useful when used with 241.Fl A . 242.El 243.\" 244.Sh RETURN VALUES 245The 246.Nm 247command will exit with 0 on success, and non-zero on errors. 248.\" 249.Sh SEE ALSO 250.Xr arp 8 251.\" 252.Sh HISTORY 253The 254.Nm 255command first appeared in the WIDE Hydrangea IPv6 protocol stack kit. 256.\" 257.\" .Sh BUGS 258.\" (to be written) 259