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28 .\" @(#)ping.8 8.2 (Berkeley) 12/11/93
39 .Tn ICMPv6 ECHO_REQUEST
40 packets to network hosts
46 .Op Fl G Ar sweepmaxsize
47 .Op Fl g Ar sweepminsize
48 .Op Fl h Ar sweepincrsize
51 .Op Fl M Cm mask | time
56 .Op Fl s Ar packetsize
62 .Op Fl 4AaDdfHLnoQqRrv
68 .Op Fl M Cm mask | time
73 .Op Fl s Ar packetsize
80 .Op Fl 6AaDdEfHNnOoquvYyZ
91 .Op Fl S Ar sourceaddr
92 .Op Fl s Ar packetsize
100 utility invoked with an IPv4 target
101 .Ns ( Ar IPv4-host No or Ar IPv4-mcast-group Ns )
104 .No protocol Ap s mandatory
106 datagram to elicit an
107 .Tn ICMP ECHO_RESPONSE
108 from a host or gateway.
114 header, followed by a
116 and then an arbitrary number of
118 bytes used to fill out the packet.
120 When invoked with an IPv6 target
121 .Ns ( Ar IPv6-host Ns ) Ns ,
125 .Tn ICMP6_ECHO_REQUEST
126 datagram to elicit an
129 .Tn ICMP6_ECHO_REQUEST
130 datagrams have an IPv6 header and
132 header formatted as documented in RFC 2463.
134 When invoked with a hostname, the version to which the target is resolved first is used.
135 In that case, the options and arguments used must be valid for the specific IP version, otherwise
138 If the target is resolved to both IPv4 and IPv6, the specific IP version can be requested by
142 options, respectively.
143 For backwards-compatibility, ICMPv6 can also be selected by invoking the binary
146 .Ss Options common to both IPv4 and IPv6 targets
147 .Bl -tag -width indent
153 character when no packet is received before the next packet
155 To cater for round-trip times that are longer than the interval
156 between transmissions, further missing packets cause a bell only
157 if the maximum number of unreceived packets has increased.
163 character in the output when any packet is received.
165 Add an 802.1p Ethernet Priority Code Point when sending a packet.
166 0..7 uses that specific PCP, -1 uses the interface default PCP (or none).
173 If this option is not specified,
175 will operate until interrupted.
177 For an IPv4 target, if this option is specified in conjunction with ping sweeps,
178 each sweep will consist of
182 Disable fragmentation.
186 option on the socket being used.
189 Outputs packets as fast as they come back or one hundred times per second,
195 is printed, while for every
197 received a backspace is printed.
198 This provides a rapid display of how many packets are being dropped.
199 Only the super-user may use this option.
201 This can be very hard on a network and should be used with caution.
205 Try to do a reverse DNS lookup when displaying addresses.
206 This is the opposite of the
212 is an IP address indentifying an interface from which the packets will be sent.
213 This flag applies only if the ping target is a multicast address.
217 is a name of an interface (e.g. `em0') from which the packets will be sent.
218 This flag applies if the ping target is a multicast address, or link-local/site-local
224 .Em between sending each packet .
225 The default is to wait for one second between each packet.
226 The wait time may be fractional, but only the super-user may specify
227 values less than 1 second.
228 This option is incompatible with the
236 sends that many packets as fast as possible before falling into its normal
238 Only the super-user may use this option.
240 For an IPv4 target, set the IP Time To Live for outgoing packets.
241 If not specified, the kernel uses the value of the
245 For an IPv6 target, set the IPv6 hoplimit.
248 No attempt will be made to lookup symbolic names for host addresses.
249 This is the opposite of
251 and it is the default behavior.
253 Exit successfully after receiving one reply packet.
256 specifies IPsec policy for the ping session.
257 For details please refer to
260 .Xr ipsec_set_policy 3 .
262 You may specify up to 16
264 bytes to fill out the packet you send.
265 This is useful for diagnosing data-dependent problems in a network.
268 will cause the sent packet to be filled with all
272 Nothing is displayed except the summary lines at startup time and
275 Use the following IP address as the source address in outgoing packets.
276 On hosts with more than one IP address, this option can be used to
277 force the source address to be something other than the IP address
278 of the interface the probe packet is sent on.
280 For IPv4, if the IP address is not one of this machine's interface
281 addresses, an error is returned and nothing is sent.
283 For IPv6, the source address must be one of the unicast addresses of
284 the sending node, and must be numeric.
285 .It Fl s Ar packetsize
286 Specify the number of data bytes to be sent.
287 The default is 56, which translates into 64
289 data bytes when combined
294 For IPv4, only the super-user may specify values more than default.
295 This option cannot be used with ping sweeps.
297 For IPv6, you may need to specify
299 as well to extend socket buffer size.
301 Specify a timeout, in seconds, before ping exits regardless of how
302 many packets have been received.
308 that are received are listed.
310 Time in milliseconds to wait for a reply for each packet sent.
311 If a reply arrives later, the packet is not printed as replied, but
312 considered as replied when calculating statistics.
314 .Ss Options only for IPv4 targets
315 .Bl -tag -width indent
317 Use IPv4 regardless of how the target is resolved.
318 .It Fl G Ar sweepmaxsize
319 Specify the maximum size of
321 payload when sending sweeping pings.
322 This option is required for ping sweeps.
323 .It Fl g Ar sweepminsize
326 payload to start with when sending sweeping pings.
327 The default value is 0.
328 .It Fl h Ar sweepincrsize
329 Specify the number of bytes to increment the size of
332 each sweep when sending sweeping pings.
333 The default value is 1.
335 Suppress loopback of multicast packets.
336 This flag only applies if the ping destination is a multicast address.
337 .It Fl M Cm mask | time
346 print the netmask of the remote machine.
348 .Va net.inet.icmp.maskrepl
349 MIB variable to enable
352 .Va net.inet.icmp.maskfake
353 if you want to override the netmask in the response.
356 print the origination, reception and transmission timestamps.
358 .Va net.inet.icmp.tstamprepl
359 MIB variable to enable or disable
360 .Dv ICMP_TSTAMPREPLY .
362 Somewhat quiet output.
364 display ICMP error messages that are in response to our query messages.
367 flag was required to display such errors, but
369 displays all ICMP error messages.
370 On a busy machine, this output can be overbearing.
375 prints out any ICMP error messages caused by its own ECHO_REQUEST
384 the route buffer on returned packets.
385 Note that the IP header is only large enough for nine such routes;
388 command is usually better at determining the route packets take to a
389 particular destination.
390 If more routes come back than should, such as due to an illegal spoofed
391 packet, ping will print the route list and then truncate it at the correct
393 Many hosts ignore or discard the
397 Bypass the normal routing tables and send directly to a host on an attached
399 If the host is not on a directly-attached network, an error is returned.
400 This option can be used to ping a local host through an interface
401 that has no route through it
402 (e.g., after the interface was dropped by
405 Set the IP Time To Live for multicasted packets.
406 This flag only applies if the ping destination is a multicast address.
408 Use the specified type of service.
410 hostname or IPv4 address of the final destination node.
411 .It Ar IPv4-mcast-group
412 IPv4 multicast address of the final destination nodes.
414 .Ss Options only for IPv6 targets
415 .Bl -tag -width indent
417 Use IPv6 regardless of how the target is resolved.
419 Set socket buffer size.
423 as the next hop to the destination.
424 The gateway must be a neighbor of the sending node.
426 Generate ICMPv6 Node Information Node Addresses query, rather than echo-request.
428 must be a string constructed of the following characters.
429 .Bl -tag -width Ds -compact
431 requests unicast addresses from all of the responder's interfaces.
432 If the character is omitted,
433 only those addresses which belong to the interface which has the
434 responder's address are requests.
436 requests responder's IPv4-compatible and IPv4-mapped addresses.
438 requests responder's global-scope addresses.
440 requests responder's site-local addresses.
442 requests responder's link-local addresses.
444 requests responder's anycast addresses.
445 Without this character, the responder will return unicast addresses only.
446 With this character, the responder will return anycast addresses only.
447 Note that the specification does not specify how to get responder's
449 This is an experimental option.
452 Probe node information multicast group address
453 .Pq Li ff02::2:ffxx:xxxx .
455 must be string hostname of the target
456 (must not be a numeric IPv6 address).
457 Node information multicast group will be computed based on given
459 and will be used as the final destination.
460 Since node information multicast group is a link-local multicast group,
461 outgoing interface needs to be specified by
465 When specified twice, the address
466 .Pq Li ff02::2:xxxx:xxxx
468 The former is in RFC 4620, the latter is in an old Internet Draft
469 draft-ietf-ipngwg-icmp-name-lookup.
470 Note that KAME-derived implementations including
474 Generate ICMPv6 Node Information supported query types query,
475 rather than echo-request.
483 asks the kernel to fragment packets to fit into the minimum IPv6 MTU.
487 will suppress the behavior in the following two levels:
488 when the option is specified once, the behavior will be disabled for
490 When the option is more than once, it will be disabled for both
491 unicast and multicast packets.
495 but with old packet format based on 03 draft.
496 This option is present for backward compatibility.
502 Generate ICMPv6 Node Information DNS Name query, rather than echo-request.
508 IPv6 addresses for intermediate nodes,
509 which will be put into type 0 routing header.
511 IPv6 address of the final destination node.
513 .Ss Experimental options only for IPv6 target
514 .Bl -tag -width indent
516 Enables transport-mode IPsec encapsulated security payload.
518 Enables transport-mode IPsec authentication header.
523 for fault isolation, it should first be run on the local host, to verify
524 that the local network interface is up and running.
525 Then, hosts and gateways further and further away should be
527 Round-trip times and packet loss statistics are computed.
528 If duplicate packets are received, they are not included in the packet
529 loss calculation, although the round trip time of these packets is used
530 in calculating the round-trip time statistics.
531 When the specified number of packets have been sent
533 or if the program is terminated with a
535 a brief summary is displayed, showing the number of packets sent and
536 received, and the minimum, mean, maximum, and standard deviation of
537 the round-trip times.
547 signal, the current number of packets sent and received, and the
548 minimum, mean, maximum, and standard deviation of the round-trip times
549 will be written to the standard output.
551 This program is intended for use in network testing, measurement and
553 Because of the load it can impose on the network, it is unwise to use
555 during normal operations or from automated scripts.
556 .Sh ICMP PACKET DETAILS
557 An IP header without options is 20 bytes.
561 packet contains an additional 8 bytes worth of
563 header followed by an arbitrary amount of data.
566 is given, this indicated the size of this extra piece of data
568 Thus the amount of data received inside of an IP packet of type
571 will always be 8 bytes more than the requested data space
576 If the data space is at least eight bytes large,
578 uses the first eight bytes of this space to include a timestamp which
579 it uses in the computation of round trip times.
580 If less than eight bytes of pad are specified, no round trip times are
582 .Sh DUPLICATE AND DAMAGED PACKETS
585 utility will report duplicate and damaged packets.
586 Duplicate packets should never occur when pinging a unicast address,
587 and seem to be caused by
588 inappropriate link-level retransmissions.
589 Duplicates may occur in many situations and are rarely
591 a good sign, although the presence of low levels of duplicates may not
592 always be cause for alarm.
593 Duplicates are expected when pinging a broadcast or multicast address,
594 since they are not really duplicates but replies from different hosts
597 Damaged packets are obviously serious cause for alarm and often
598 indicate broken hardware somewhere in the
600 packet's path (in the network or in the hosts).
601 .Sh TRYING DIFFERENT DATA PATTERNS
604 layer should never treat packets differently depending on the data
605 contained in the data portion.
606 Unfortunately, data-dependent problems have been known to sneak into
607 networks and remain undetected for long periods of time.
608 In many cases the particular pattern that will have problems is something
609 that does not have sufficient
611 such as all ones or all zeros, or a pattern right at the edge, such as
614 necessarily enough to specify a data pattern of all zeros (for example)
615 on the command line because the pattern that is of interest is
616 at the data link level, and the relationship between what you type and
617 what the controllers transmit can be complicated.
619 This means that if you have a data-dependent problem you will probably
620 have to do a lot of testing to find it.
621 If you are lucky, you may manage to find a file that either
623 be sent across your network or that takes much longer to transfer than
624 other similar length files.
625 You can then examine this file for repeated patterns that you can test
633 value of an IP packet represents the maximum number of IP routers
634 that the packet can go through before being thrown away.
635 In current practice you can expect each router in the Internet to decrement
638 field by exactly one.
642 specification recommends setting the
646 packets to 64, but many systems use smaller values
652 The maximum possible value of this field is 255, and most
658 .Tn ICMP ECHO_REQUEST
660 This is why you will find you can
662 some hosts, but not reach them with
669 prints the ttl value from the packet it receives.
670 When a remote system receives a ping packet, it can do one of three things
673 field in its response:
676 Not change it; this is what
678 systems did before the
683 value in the received packet will be 255 minus the
684 number of routers in the round-trip path.
686 Set it to 255; this is what current
691 value in the received packet will be 255 minus the
692 number of routers in the path
700 Set it to some other value.
701 Some machines use the same value for
703 packets that they use for
705 packets, for example either 30 or 60.
706 Others may use completely wild values.
711 utility exits with one of the following values:
712 .Bl -tag -width indent
714 At least one response was heard from the specified
717 The transmission was successful but no responses were received.
722 The following will send ICMPv6 echo request to
724 .Bd -literal -offset indent
725 ping -6 -n dst.foo.com
728 The following will probe hostnames for all nodes on the network link attached to
733 is named the link-local all-node multicast address, and the packet would
734 reach every node on the network link.
735 .Bd -literal -offset indent
736 ping -6 -y ff02::1%wi0
739 The following will probe addresses assigned to the destination node,
741 .Bd -literal -offset indent
742 ping -6 -k agl dst.foo.com
757 .%T "Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification"
763 .%T "IPv6 Node Information Queries"
764 .%N draft-ietf-ipngwg-icmp-name-lookups-09.txt
766 .%O work in progress material
775 utility with IPv6 support first appeared in the WIDE Hydrangea IPv6
778 IPv6 and IPsec support based on the KAME Project
779 .Pq Pa http://www.kame.net/
780 stack was initially integrated into
785 utility was merged to
787 in Google Summer of Code 2019.
791 utility was written by
793 while at the US Army Ballistics
796 Many Hosts and Gateways ignore the IPv4
800 The maximum IP header length is too small for options like
802 to be completely useful.
804 not much that can be done about this, however.
806 Flood pinging is not recommended in general, and flood pinging the
807 broadcast address should only be done under very controlled conditions.
811 option is not worth much on busy hosts.
projects / FreeBSD / FreeBSD.git / blob