1.\" $NetBSD: ndp.8,v 1.25 2009/11/06 20:51:43 dyoung 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 November 6, 2009 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, 184even if the flag 185.Ic accept_rtadv 186is on, unless either the 187.Li net.inet6.ip6.accept_rtadv 188variable is non-0, or the flag 189.Ic override_rtadv 190is on. 191This flag is set to 1 by default. 192.It Ic override_rtadv 193Specify whether or not to override the 194.Li net.inet6.ip6.accept_rtadv 195variable. 196If the flag is on, then it will suffice to set the flag 197.Ic accept_rtadv 198to make the kernel accept Router Advertisement messages on the 199.Ar interface . 200This flag is set to 0 by default. 201.It Ic prefer_source 202Prefer addresses on the 203.Ar interface 204as candidates of the source address for outgoing packets. 205The default value of this flag is off. 206For more details about the entire algorithm of source address 207selection, see the 208.Pa IMPLEMENTATION 209file supplied with the KAME kit. 210.It Ic disabled 211Disable IPv6 operation on the interface. 212When disabled, the interface discards any IPv6 packets 213received on or being sent to the interface. 214In the sending case, an error of ENETDOWN will be returned to the 215application. 216This flag is typically set automatically in the kernel as a result of 217a certain failure of Duplicate Address Detection. 218While the flag can be set or cleared by hand with the 219.Nm 220command, it is not generally advisable to modify this flag manually. 221.It Ic basereachable=(number) 222Specify the BaseReachbleTimer on the interface in millisecond. 223.It Ic retrans=(number) 224Specify the RetransTimer on the interface in millisecond. 225.It Ic curhlim=(number) 226Specify the Cur Hop Limit on the interface. 227.El 228.It Fl n 229Do not try to resolve numeric addresses to hostnames. 230.It Fl p 231Show prefix list. 232.It Fl P 233Flush all the entries in the prefix list. 234.It Fl r 235Show default router list. 236.It Fl R 237Flush all the entries in the default router list. 238.It Fl s 239Register an NDP entry for a node. 240The entry will be permanent unless the word 241.Li temp 242is given in the command. 243If the word 244.Li proxy 245is given, this system will act as a proxy NDP server, 246responding to requests for 247.Ar hostname 248even though the host address is not its own. 249.It Fl t 250Print timestamp on each entry, 251making it possible to merge output with 252.Xr tcpdump 8 . 253Most useful when used with 254.Fl A . 255.El 256.\" 257.Sh RETURN VALUES 258The 259.Nm 260command will exit with 0 on success, and non-zero on errors. 261.\" 262.Sh SEE ALSO 263.Xr arp 8 264.\" 265.Sh HISTORY 266The 267.Nm 268command first appeared in the WIDE Hydrangea IPv6 protocol stack kit. 269.\" 270.\" .Sh BUGS 271.\" (to be written) 272