1.\" $NetBSD: ping6.8,v 1.34 2021/06/07 22:13:34 dholland Exp $ 2.\" $KAME: ping6.8,v 1.57 2002/05/26 13:18:25 itojun 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 June 7, 2021 32.Dt PING6 8 33.Os 34.Sh NAME 35.Nm ping6 36.Nd send ICMPv6 ECHO_REQUEST packets to network hosts 37.Sh SYNOPSIS 38.Nm ping6 39.\" without IPsec, or new IPsec 40.Op Fl dfHmnNoqtvwW 41.\" old IPsec 42.\" .Op Fl AdEfnNqRtvwW 43.Op Fl a Ar addrtype 44.Op Fl b Ar bufsiz 45.Op Fl c Ar count 46.Op Fl g Ar gateway 47.Op Fl h Ar hoplimit 48.Op Fl I Ar interface 49.Op Fl i Ar wait 50.Op Fl l Ar preload 51.\" new IPsec 52.Op Fl P Ar policy 53.Op Fl p Ar pattern 54.Op Fl S Ar sourceaddr 55.Op Fl s Ar packetsize 56.Op Fl X Ar deadline 57.Op Fl x Ar maxwait 58.Ar host 59.Sh DESCRIPTION 60.Nm 61uses the ICMPv6 protocol's mandatory 62.Dv ICMP6_ECHO_REQUEST 63datagram to elicit an 64.Dv ICMP6_ECHO_REPLY 65from a host or gateway. 66.Dv ICMP6_ECHO_REQUEST 67datagrams (``pings'') have an IPv6 header, 68and ICMPv6 header formatted as documented in RFC 2463. 69The options are as follows: 70.Bl -tag -width Ds 71.\" old IPsec 72.\" .It Fl A 73.\" Enables transport-mode IPsec authentication header 74.\" .Pq experimental . 75.It Fl a Ar addrtype 76Generate ICMPv6 Node Information Node Addresses query, rather than echo-request. 77.Ar addrtype 78must be a string constructed of the following characters. 79.Bl -tag -width Ds -compact 80.It Ic a 81requests unicast addresses from all of the responder's interfaces. 82If the character is omitted, 83only those addresses which belong to the interface which has the 84responder's address are requests. 85.It Ic c 86requests responder's IPv4-compatible and IPv4-mapped addresses. 87.It Ic g 88requests responder's global-scope addresses. 89.It Ic s 90requests responder's site-local addresses. 91.It Ic l 92requests responder's link-local addresses. 93.It Ic A 94requests responder's anycast addresses. 95Without this character, the responder will return unicast addresses only. 96With this character, the responder will return anycast addresses only. 97Note that the specification does not specify how to get responder's 98anycast addresses. 99This is an experimental option. 100.El 101.It Fl b Ar bufsiz 102Set socket buffer size. 103.It Fl c Ar count 104Stop after sending 105.Pq and receiving 106.Ar count 107.Dv ECHO_RESPONSE 108packets. 109.It Fl d 110Set the 111.Dv SO_DEBUG 112option on the socket being used. 113.\" .It Fl E 114.\" Enables transport-mode IPsec encapsulated security payload 115.\" .Pq experimental . 116.It Fl f 117Flood ping. 118Outputs packets as fast as they come back or one hundred times per second, 119whichever is more. 120For every 121.Dv ECHO_REQUEST 122sent a period 123.Dq \&. 124is printed, while for every 125.Dv ECHO_REPLY 126received a backspace is printed. 127This provides a rapid display of how many packets are being dropped. 128Only the super-user may use this option. 129.Bf -emphasis 130This can be very hard on a network and should be used with caution. 131.Ef 132.It Fl g Ar gateway 133Specifies to use 134.Ar gateway 135as the next hop to the destination. 136The gateway must be a neighbor of the sending node. 137.It Fl H 138Specifies to try reverse-lookup of IPv6 addresses. 139The 140.Nm 141command does not try reverse-lookup unless the option is specified. 142.It Fl h Ar hoplimit 143Set the IPv6 hoplimit. 144.It Fl I Ar interface 145Source packets with the given interface address. 146This flag applies if the ping destination is a multicast address, 147or link-local/site-local unicast address. 148.It Fl i Ar wait 149Wait 150.Ar wait 151seconds 152.Em between sending each packet . 153The default is to wait for one second between each packet. 154This option is incompatible with the 155.Fl f 156option. 157.It Fl l Ar preload 158If 159.Ar preload 160is specified, 161.Nm 162sends that many packets as fast as possible before falling into its normal 163mode of behavior. 164Only the super-user may use this option. 165.It Fl m 166By default, 167.Nm 168asks the kernel to fragment packets to fit into the minimum IPv6 MTU. 169.Fl m 170will suppress the behavior in the following two levels: 171when the option is specified once, the behavior will be disabled for 172unicast packets. 173When the option is specified more than once, it will be disabled for both 174unicast and multicast packets. 175.It Fl N 176Probe node information multicast group 177.Pq Li ff02::2:xxxx:xxxx . 178.Ar host 179must be string hostname of the target 180.Pq must not be a numeric IPv6 address . 181Node information multicast group will be computed based on given 182.Ar host , 183and will be used as the final destination. 184Since node information multicast group is a link-local multicast group, 185outgoing interface needs to be specified by 186.Fl I 187option. 188.It Fl n 189Numeric output only. 190No attempt will be made to lookup symbolic names from addresses in the reply. 191.It Fl o 192Exit successfully after receiving one reply packet. 193.It Fl P Ar policy 194.Ar policy 195specifies IPsec policy to be used for the probe. 196.It Fl p Ar pattern 197You may specify up to 16 198.Dq pad 199bytes to fill out the packet you send. 200This is useful for diagnosing data-dependent problems in a network. 201For example, 202.Dq Li \-p ff 203will cause the sent packet to be filled with all 204ones. 205Note that for IPv6 there is no fill space by default so it is 206necessary to also use the 207.Fl s 208option to expand the packet. 209.\" new IPsec 210.It Fl q 211Quiet output. 212Nothing is displayed except the summary lines at startup time and 213when finished. 214.It Fl S Ar sourceaddr 215Specifies the source address of request packets. 216The source address must be one of the unicast addresses of the sending node, 217and must be numeric. 218.It Fl s Ar packetsize 219Specifies the number of data bytes to be sent. 220The default is 56, which translates into 64 ICMP data bytes when combined 221with the 8 bytes of ICMP header data. 222You may need to specify 223.Fl b 224as well to extend socket buffer size. 225.It Fl t 226Generate ICMPv6 Node Information supported query types query, 227rather than echo-request. 228.Fl s 229has no effect if 230.Fl t 231is specified. 232.It Fl v 233Verbose output. 234ICMP packets other than 235.Dv ECHO_RESPONSE 236that are received are listed. 237.It Fl W 238Same as 239.Fl w , 240but with old packet format based on 03 draft. 241This option is present for backward compatibility. 242.Fl s 243has no effect if 244.Fl w 245is specified. 246.It Fl w 247Generate ICMPv6 Node Information DNS Name query, rather than echo-request. 248.Fl s 249has no effect if 250.Fl w 251is specified. 252.It Fl X Ar deadline 253Specify a timeout, in seconds, before ping exits regardless of 254how many packets have been received. 255.It Ar host 256IPv6 address of the final destination node. 257.It Fl x Ar maxwait 258Time in milliseconds to wait for a reply for each packet sent. 259.El 260.Pp 261When using 262.Nm 263for fault isolation, it should first be run on the local host, to verify 264that the local network interface is up and running. 265Then, hosts and gateways further and further away should be 266.Dq pinged . 267Round-trip times and packet loss statistics are computed. 268If duplicate packets are received, they are not included in the packet 269loss calculation, although the round trip time of these packets is used 270in calculating the round-trip time statistics. 271When the specified number of packets have been sent 272.Pq and received 273or if the program is terminated with a 274.Dv SIGINT , 275a brief summary is displayed, showing the number of packets sent and 276received, and the minimum, maximum, mean, and standard deviation of 277the round-trip times. 278.Pp 279This program is intended for use in network testing, measurement and 280management. 281Because of the load it can impose on the network, it is unwise to use 282.Nm 283during normal operations or from automated scripts. 284.\" .Sh ICMP PACKET DETAILS 285.\" An IP header without options is 20 bytes. 286.\" An 287.\" ICMP 288.\" .Dv ECHO_REQUEST 289.\" packet contains an additional 8 bytes worth of 290.\" ICMP 291.\" header followed by an arbitrary amount of data. 292.\" When a 293.\" .Ar packetsize 294.\" is given, this indicated the size of this extra piece of data 295.\" .Pq the default is 56 . 296.\" Thus the amount of data received inside of an IP packet of type 297.\" ICMP 298.\" .Dv ECHO_REPLY 299.\" will always be 8 bytes more than the requested data space 300.\" .Pq the ICMP header . 301.\" .Pp 302.\" If the data space is at least eight bytes large, 303.\" .Nm 304.\" uses the first eight bytes of this space to include a timestamp which 305.\" it uses in the computation of round trip times. 306.\" If less than eight bytes of pad are specified, no round trip times are 307.\" given. 308.Sh DUPLICATE AND DAMAGED PACKETS 309.Nm 310will report duplicate and damaged packets. 311Duplicate packets should never occur when pinging a unicast address, 312and seem to be caused by 313inappropriate link-level retransmissions. 314Duplicates may occur in many situations and are rarely 315.Pq if ever 316a good sign, although the presence of low levels of duplicates may not 317always be cause for alarm. 318Duplicates are expected when pinging a multicast address, 319since they are not really duplicates but replies from different hosts 320to the same request. 321.Pp 322Damaged packets are obviously serious cause for alarm and often 323indicate broken hardware somewhere in the 324.Nm 325packet's path 326.Pq in the network or in the hosts . 327.Sh TRYING DIFFERENT DATA PATTERNS 328The 329(inter)network 330layer should never treat packets differently depending on the data 331contained in the data portion. 332Unfortunately, data-dependent problems have been known to sneak into 333networks and remain undetected for long periods of time. 334In many cases the particular pattern that will have problems is something 335that does not have sufficient 336.Dq transitions , 337such as all ones or all zeros, or a pattern right at the edge, such as 338almost all zeros. 339It is not 340necessarily enough to specify a data pattern of all zeros (for example) 341on the command line because the pattern that is of interest is 342at the data link level, and the relationship between what you type and 343what the controllers transmit can be complicated. 344.Pp 345This means that if you have a data-dependent problem you will probably 346have to do a lot of testing to find it. 347If you are lucky, you may manage to find a file that either 348cannot 349be sent across your network or that takes much longer to transfer than 350other similar length files. 351You can then examine this file for repeated patterns that you can test 352using the 353.Fl p 354option of 355.Nm . 356.Sh EXIT STATUS 357.Nm 358exits with 0 on success (the host is alive), 359and non-zero if the arguments are incorrect or the host is not responding. 360.Sh EXAMPLES 361Normally, 362.Nm 363works just like 364.Xr ping 8 365would work; the following will send ICMPv6 echo request to 366.Li dst.foo.com . 367.Bd -literal -offset indent 368ping6 -n dst.foo.com 369.Ed 370.Pp 371The following will probe hostnames for all nodes on the network link attached to 372.Li wi0 373interface. 374The address 375.Li ff02::1 376is named the link-local all-node multicast address, and the packet would 377reach every node on the network link. 378.Bd -literal -offset indent 379ping6 -w ff02::1%wi0 380.Ed 381.Pp 382The following will probe addresses assigned to the destination node, 383.Li dst.foo.com . 384.Bd -literal -offset indent 385ping6 -a agl dst.foo.com 386.Ed 387.Sh SEE ALSO 388.Xr netstat 1 , 389.Xr icmp6 4 , 390.Xr inet6 4 , 391.Xr ip6 4 , 392.Xr ifconfig 8 , 393.Xr ping 8 , 394.Xr routed 8 , 395.Xr traceroute 8 , 396.Xr traceroute6 8 397.Rs 398.%A A. Conta 399.%A S. Deering 400.%T "Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification" 401.%N RFC 2463 402.%D December 1998 403.Re 404.Rs 405.%A Matt Crawford 406.%T "IPv6 Node Information Queries" 407.%N draft-ietf-ipngwg-icmp-name-lookups-09.txt 408.%D May 2002 409.%O work in progress material 410.Re 411.Sh HISTORY 412The 413.Xr ping 8 414command appeared in 415.Bx 4.3 . 416The 417.Nm 418command with IPv6 support first appeared in the WIDE Hydrangea IPv6 419protocol stack kit. 420.Sh BUGS 421.\" except for bsdi 422.Nm 423is intentionally separate from 424.Xr ping 8 . 425