ping6.tproj/ping6.8

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  30 .\"     $FreeBSD: src/sbin/ping6/ping6.8,v 1.3.2.8 2001/07/06 08:56:46 ume Exp $
  31 .\"
  32 .Dd May 17, 1998
  33 .Dt PING6 8
  34 .Os
  35 .Sh NAME
  36 .Nm ping6
  37 .Nd send
  38 .Tn ICMPv6 ECHO_REQUEST
  39 packets to network hosts
  40 .Sh SYNOPSIS
  41 .Nm
  42 .\" without ipsec, or new ipsec
  43 .Op Fl dfHnNqRtvwW
  44 .\" old ipsec
  45 .\" .Op Fl AdEfnNqRtvwW
  46 .Bk -words
  47 .Op Fl a Ar addrtype
  48 .Ek
  49 .Bk -words
  50 .Op Fl b Ar bufsiz
  51 .Ek
  52 .Bk -words
  53 .Op Fl c Ar count
  54 .Ek
  55 .Bk -words
  56 .Op Fl h Ar hoplimit
  57 .Ek
  58 .Bk -words
  59 .Op Fl I Ar interface
  60 .Ek
  61 .Bk -words
  62 .Op Fl i Ar wait
  63 .Ek
  64 .Bk -words
  65 .Op Fl l Ar preload
  66 .Ek
  67 .Bk -words
  68 .Op Fl p Ar pattern
  69 .Ek
  70 .Bk -words
  71 .\" new ipsec
  72 .Op Fl P Ar policy
  73 .Ek
  74 .Bk -words
  75 .Op Fl S Ar sourceaddr
  76 .Ek
  77 .Bk -words
  78 .Op Fl s Ar packetsize
  79 .Ek
  80 .Bk -words
  81 .Op Ar hops...\&
  82 .Ek
  83 .Bk -words
  84 .Ar host
  85 .Ek
  86 .Sh DESCRIPTION
  87 .Nm
  88 uses the
  89 .Tn ICMPv6
  90 protocol's mandatory
  91 .Tn ICMP6_ECHO_REQUEST
  92 datagram to elicit an
  93 .Tn ICMP6_ECHO_REPLY
  94 from a host or gateway.
  95 .Tn ICMP6_ECHO_REQUEST
  96 datagrams (``pings'') have an IPv6 header,
  97 and
  98 .Tn ICMPv6
  99 header formatted as documented in RFC2463.
 100 The options are as follows:
 101 .Bl -tag -width Ds
 102 .\" old ipsec
 103 .\" .It Fl A
 104 .\" Enables transport-mode IPsec authentication header
 105 .\" .Pq experimental .
 106 .It Fl a Ar addrtype
 107 Generate ICMPv6 Node Information Node Addresses query, rather than echo-request.
 108 .Ar addrtype
 109 must be a string constructed of the following characters.
 110 .Bl -tag -width Ds -compact
 111 .It Ic a
 112 requests all the responder's unicast addresses.
 113 If the character is omitted,
 114 only those addresses which belong to the interface which has the
 115 responder's address are requests.
 116 .It Ic c
 117 requests responder's IPv4-compatible and IPv4-mapped addresses.
 118 .It Ic g
 119 requests responder's global-scope addresses.
 120 .It Ic s
 121 requests responder's site-local addresses.
 122 .It Ic l
 123 requests responder's link-local addresses.
 124 .It Ic A
 125 requests responder's anycast addresses.
 126 Without this character, the responder will return unicast addresses only.
 127 With this character, the responder will return anycast addresses only.
 128 Note that the specification does not specify how to get responder's
 129 anycast addresses.
 130 This is an experimental option.
 131 .El
 132 .It Fl b Ar bufsiz
 133 Set socket buffer size.
 134 .It Fl c Ar count
 135 Stop after sending
 136 .Pq and receiving
 137 .Ar count
 138 .Tn ECHO_RESPONSE
 139 packets.
 140 .It Fl d
 141 Set the
 142 .Dv SO_DEBUG
 143 option on the socket being used.
 144 .\" .It Fl E
 145 .\" Enables transport-mode IPsec encapsulated security payload
 146 .\" .Pq experimental .
 147 .It Fl f
 148 Flood ping.
 149 Outputs packets as fast as they come back or one hundred times per second,
 150 whichever is more.
 151 For every
 152 .Tn ECHO_REQUEST
 153 sent a period
 154 .Dq .\&
 155 is printed, while for every
 156 .Tn ECHO_REPLY
 157 received a backspace is printed.
 158 This provides a rapid display of how many packets are being dropped.
 159 Only the super-user may use this option.
 160 .Bf -emphasis
 161 This can be very hard on a network and should be used with caution.
 162 .Ef
 163 .It Fl H
 164 Specifies to try reverse-lookup of IPv6 addresses.
 165 The
 166 .Nm
 167 command does not try reverse-lookup unless the option is specified.
 168 .It Fl h Ar hoplimit
 169 Set the IPv6 hoplimit.
 170 .It Fl I Ar interface
 171 Source packets with the given interface address.
 172 This flag applies if the ping destination is a multicast address,
 173 or link-local/site-local unicast address.
 174 .It Fl i Ar wait
 175 Wait
 176 .Ar wait
 177 seconds
 178 .Em between sending each packet .
 179 The default is to wait for one second between each packet.
 180 This option is incompatible with the
 181 .Fl f
 182 option.
 183 .It Fl l Ar preload
 184 If
 185 .Ar preload
 186 is specified,
 187 .Nm
 188 sends that many packets as fast as possible before falling into its normal
 189 mode of behavior.
 190 Only the super-user may use this option.
 191 .It Fl n
 192 Numeric output only.
 193 No attempt will be made to lookup symbolic names from addresses in the reply.
 194 .It Fl N
 195 Probe node information multicast group
 196 .Pq Li ff02::2:xxxx:xxxx .
 197 .Ar host
 198 must be string hostname of the target
 199 .Pq must not be a numeric IPv6 address .
 200 Node information multicast group will be computed based on given
 201 .Ar host ,
 202 and will be used as the final destination.
 203 Since node information multicast group is a link-local multicast group,
 204 destination link needs to be specified by
 205 .Fl I
 206 option.
 207 .It Fl p Ar pattern
 208 You may specify up to 16
 209 .Dq pad
 210 bytes to fill out the packet you send.
 211 This is useful for diagnosing data-dependent problems in a network.
 212 For example,
 213 .Dq Li \-p ff
 214 will cause the sent packet to be filled with all
 215 ones.
 216 .\" new ipsec
 217 .It Fl P Ar policy
 218 .Ar policy
 219 specifies IPsec policy to be used for the probe.
 220 .It Fl q
 221 Quiet output.
 222 Nothing is displayed except the summary lines at startup time and
 223 when finished.
 224 .It Fl R
 225 Make the kernel believe that the target
 226 .Ar host
 227 .Po
 228 or the first
 229 .Ar hop
 230 if you specify
 231 .Ar hops
 232 .Pc
 233 is reachable, by injecting upper-layer reachability confirmation hint.
 234 The option is meaningful only if the target
 235 .Ar host
 236 .Pq or the first hop
 237 is a neighbor.
 238 .It Fl S Ar sourceaddr
 239 Specifies the source address of request packets.
 240 The source address must be one of the unicast addresses of the sending node.
 241 If the outgoing interface is specified by the
 242 .Fl I
 243 option as well,
 244 .Ar sourceaddr
 245 needs to be an address assigned to the specified interface.
 246 .It Fl s Ar packetsize
 247 Specifies the number of data bytes to be sent.
 248 The default is 56, which translates into 64
 249 .Tn ICMP
 250 data bytes when combined
 251 with the 8 bytes of
 252 .Tn ICMP
 253 header data.
 254 You may need to specify
 255 .Fl b
 256 as well to extend socket buffer size.
 257 .It Fl t
 258 Generate ICMPv6 Node Information supported query types query,
 259 rather than echo-request.
 260 .Fl s
 261 has no effect if
 262 .Fl t
 263 is specified.
 264 .It Fl v
 265 Verbose output.
 266 .Tn ICMP
 267 packets other than
 268 .Tn ECHO_RESPONSE
 269 that are received are listed.
 270 .It Fl w
 271 Generate ICMPv6 Node Information DNS Name query, rather than echo-request.
 272 .Fl s
 273 has no effect if
 274 .Fl w
 275 is specified.
 276 .It Fl W
 277 Same as
 278 .Fl w ,
 279 but with old packet format based on 03 draft.
 280 This option is present for backward compatibility.
 281 .Fl s
 282 has no effect if
 283 .Fl w
 284 is specified.
 285 .It Ar hops
 286 IPv6 addresses for intermediate nodes,
 287 which will be put into type 0 routing header.
 288 .It Ar host
 289 IPv6 adddress of the final destination node.
 290 .El
 291 .Pp
 292 When using
 293 .Nm
 294 for fault isolation, it should first be run on the local host, to verify
 295 that the local network interface is up and running.
 296 Then, hosts and gateways further and further away should be
 297 .Dq pinged .
 298 Round-trip times and packet loss statistics are computed.
 299 If duplicate packets are received, they are not included in the packet
 300 loss calculation, although the round trip time of these packets is used
 301 in calculating the round-trip time statistics.
 302 When the specified number of packets have been sent
 303 .Pq and received
 304 or if the program is terminated with a
 305 .Dv SIGINT ,
 306 a brief summary is displayed, showing the number of packets sent and
 307 received, and the minimum, maximum, mean, and standard deviation of
 308 the round-trip times.
 309 .Pp
 310 This program is intended for use in network testing, measurement and
 311 management.
 312 Because of the load it can impose on the network, it is unwise to use
 313 .Nm
 314 during normal operations or from automated scripts.
 315 .\" .Sh ICMP PACKET DETAILS
 316 .\" An IP header without options is 20 bytes.
 317 .\" An
 318 .\" .Tn ICMP
 319 .\" .Tn ECHO_REQUEST
 320 .\" packet contains an additional 8 bytes worth of
 321 .\" .Tn ICMP
 322 .\" header followed by an arbitrary amount of data.
 323 .\" When a
 324 .\" .Ar packetsize
 325 .\" is given, this indicated the size of this extra piece of data
 326 .\" .Pq the default is 56 .
 327 .\" Thus the amount of data received inside of an IP packet of type
 328 .\" .Tn ICMP
 329 .\" .Tn ECHO_REPLY
 330 .\" will always be 8 bytes more than the requested data space
 331 .\" .Pq the Tn ICMP header .
 332 .\" .Pp
 333 .\" If the data space is at least eight bytes large,
 334 .\" .Nm
 335 .\" uses the first eight bytes of this space to include a timestamp which
 336 .\" it uses in the computation of round trip times.
 337 .\" If less than eight bytes of pad are specified, no round trip times are
 338 .\" given.
 339 .Sh DUPLICATE AND DAMAGED PACKETS
 340 .Nm
 341 will report duplicate and damaged packets.
 342 Duplicate packets should never occur when pinging a unicast address,
 343 and seem to be caused by
 344 inappropriate link-level retransmissions.
 345 Duplicates may occur in many situations and are rarely
 346 .Pq if ever
 347 a good sign, although the presence of low levels of duplicates may not
 348 always be cause for alarm.
 349 Duplicates are expected when pinging a broadcast or multicast address,
 350 since they are not really duplicates but replies from different hosts
 351 to the same request.
 352 .Pp
 353 Damaged packets are obviously serious cause for alarm and often
 354 indicate broken hardware somewhere in the
 355 .Nm
 356 packet's path
 357 .Pq in the network or in the hosts .
 358 .Sh TRYING DIFFERENT DATA PATTERNS
 359 The
 360 (inter)network
 361 layer should never treat packets differently depending on the data
 362 contained in the data portion.
 363 Unfortunately, data-dependent problems have been known to sneak into
 364 networks and remain undetected for long periods of time.
 365 In many cases the particular pattern that will have problems is something
 366 that does not have sufficient
 367 .Dq transitions ,
 368 such as all ones or all zeros, or a pattern right at the edge, such as
 369 almost all zeros.
 370 It is not
 371 necessarily enough to specify a data pattern of all zeros (for example)
 372 on the command line because the pattern that is of interest is
 373 at the data link level, and the relationship between what you type and
 374 what the controllers transmit can be complicated.
 375 .Pp
 376 This means that if you have a data-dependent problem you will probably
 377 have to do a lot of testing to find it.
 378 If you are lucky, you may manage to find a file that either
 379 cannot
 380 be sent across your network or that takes much longer to transfer than
 381 other similar length files.
 382 You can then examine this file for repeated patterns that you can test
 383 using the
 384 .Fl p
 385 option of
 386 .Nm .
 387 .Sh RETURN VALUES
 388 .Nm
 389 returns 0 on success (the host is alive),
 390 and non-zero if the arguments are incorrect or the host is not responding.
 391 .Sh EXAMPLES
 392 Normally,
 393 .Xr ping6 8
 394 works just like
 395 .Xr ping 8
 396 would work; the following will send ICMPv6 echo request to
 397 .Li dst.foo.com .
 398 .Bd -literal -offset indent
 399 ping6 -n dst.foo.com
 400 .Ed
 401 .Pp
 402 The following will probe hostnames for all nodes on the network link attached to
 403 .Li wi0
 404 interface.
 405 The address
 406 .Li ff02::1
 407 is named the link-local all-node multicast address, and the packet would
 408 reach every node on the network link.
 409 .Bd -literal -offset indent
 410 ping6 -w ff02::1%wi0
 411 .Ed
 412 .Pp
 413 The following will probe addresses assigned to the destination node,
 414 .Li dst.foo.com .
 415 .Bd -literal -offset indent
 416 ping6 -a agl dst.foo.com
 417 .Ed
 418 .Pp
 419 .Sh SEE ALSO
 420 .Xr netstat 1 ,
 421 .Xr icmp6 4 ,
 422 .Xr inet6 4 ,
 423 .Xr ip6 4 ,
 424 .Xr ifconfig 8 ,
 425 .Xr ping 8 ,
 426 .Xr routed 8 ,
 427 .Xr traceroute 8 ,
 428 .Xr traceroute6 8
 429 .Rs
 430 .%A A. Conta
 431 .%A S. Deering
 432 .%T "Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification"
 433 .%N RFC2463
 434 .%D December 1998
 435 .Re
 436 .Rs
 437 .%A Matt Crawford
 438 .%T "IPv6 Node Information Queries"
 439 .%N draft-ietf-ipngwg-icmp-name-lookups-07.txt
 440 .%D August 2000
 441 .%O work in progress material
 442 .Re
 443 .Sh BUGS
 444 There have been many discussions on why we separate
 445 .Xr ping6 8
 446 and
 447 .Xr ping 8 .
 448 Some people argued that it would be more convenient to uniform the
 449 ping command for both IPv4 and IPv6.
 450 The followings are an answer to the request.
 451 .Pp
 452 From a developer's point of view:
 453 since the underling raw sockets API is totally different between IPv4
 454 and IPv6, we would end up having two types of code base.
 455 There would actually be less benefit to uniform the two commands
 456 into a single command from the developer's standpoint.
 457 .Pp
 458 From an operator's point of view: unlike ordinary network applications
 459 like remote login tools, we are usually aware of address family when using
 460 network management tools.
 461 We do not just want to know the reachability to the host, but want to know the
 462 reachability to the host via a particular network protocol such as
 463 IPv6.
 464 Thus, even if we had a unified
 465 .Xr ping 8
 466 command for both IPv4 and IPv6, we would usually type a
 467 .Fl 6
 468 or
 469 .Fl 4
 470 option (or something like those) to specify the particular address family.
 471 This essentially means that we have two different commands.
 472 .Sh HISTORY
 473 The
 474 .Xr ping 8
 475 command appeared in
 476 .Bx 4.3 .
 477 The
 478 .Nm
 479 command with IPv6 support first appeared in WIDE Hydrangea IPv6 protocol stack
 480 kit.
 481 .Pp
 482 IPv6 and IPsec support based on the KAME Project (http://www.kame.net/) stack
 483 was initially integrated into
 484 .Fx 4.0