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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
135 resolved first is used. In that case, the options and arguments used
136 must be valid for the specific IP version, otherwise
138 exits with an error. If the target is resolved to both IPv4 and IPv6,
139 the specific IP version can be requested by
143 options, respectively.
144 For backwards-compatibility, ICMPv6 can also be selected by invoking the binary
147 .Ss Options common to both IPv4 and IPv6 targets
148 .Bl -tag -width indent
154 character when no packet is received before the next packet
156 To cater for round-trip times that are longer than the interval
157 between transmissions, further missing packets cause a bell only
158 if the maximum number of unreceived packets has increased.
164 character in the output when any packet is received.
166 Add an 802.1p Ethernet Priority Code Point when sending a packet.
167 0..7 uses that specific PCP, -1 uses the interface default PCP (or none).
174 If this option is not specified,
176 will operate until interrupted.
178 For an IPv4 target, if this option is specified in conjunction with ping sweeps,
179 each sweep will consist of
183 Disable fragmentation.
187 option on the socket being used.
190 Outputs packets as fast as they come back or one hundred times per second,
196 is printed, while for every
198 received a backspace is printed.
199 This provides a rapid display of how many packets are being dropped.
200 Only the super-user may use this option.
202 This can be very hard on a network and should be used with caution.
206 Try to do a reverse DNS lookup when displaying addresses.
207 This is the opposite of the
213 is an IP address indentifying an interface from which the packets will
214 be sent. This flag applies only if the ping target is a multicast
219 is a name of an interface (e.g. `em0') from which the packets will be
220 sent. This flag applies if the ping target is a multicast address, or
221 link-local/site-local unicast address.
226 .Em between sending each packet .
227 The default is to wait for one second between each packet.
228 The wait time may be fractional, but only the super-user may specify
229 values less than 1 second.
230 This option is incompatible with the
238 sends that many packets as fast as possible before falling into its normal
240 Only the super-user may use this option.
242 For an IPv4 target, set the IP Time To Live for outgoing packets.
243 If not specified, the kernel uses the value of the
247 For an IPv6 target, set the IPv6 hoplimit.
250 No attempt will be made to lookup symbolic names for host addresses.
251 This is the opposite of
253 and it is the default behavior.
255 Exit successfully after receiving one reply packet.
258 specifies IPsec policy for the ping session.
259 For details please refer to
262 .Xr ipsec_set_policy 3 .
264 You may specify up to 16
266 bytes to fill out the packet you send.
267 This is useful for diagnosing data-dependent problems in a network.
270 will cause the sent packet to be filled with all
274 Nothing is displayed except the summary lines at startup time and
277 Use the following IP address as the source address in outgoing packets.
278 On hosts with more than one IP address, this option can be used to
279 force the source address to be something other than the IP address
280 of the interface the probe packet is sent on.
282 For IPv4, if the IP address is not one of this machine's interface
283 addresses, an error is returned and nothing is sent.
285 For IPv6, the source address must be one of the unicast addresses of
286 the sending node, and must be numeric.
287 .It Fl s Ar packetsize
288 Specify the number of data bytes to be sent.
289 The default is 56, which translates into 64
291 data bytes when combined
296 For IPv4, only the super-user may specify values more than default.
297 This option cannot be used with ping sweeps.
299 For IPv6, you may need to specify
301 as well to extend socket buffer size.
303 Specify a timeout, in seconds, before ping exits regardless of how
304 many packets have been received.
310 that are received are listed.
312 Time in milliseconds to wait for a reply for each packet sent.
313 If a reply arrives later, the packet is not printed as replied, but
314 considered as replied when calculating statistics.
316 .Ss Options only for IPv4 targets
317 .Bl -tag -width indent
319 Use IPv4 regardless of how the target is resolved.
320 .It Fl G Ar sweepmaxsize
321 Specify the maximum size of
323 payload when sending sweeping pings.
324 This option is required for ping sweeps.
325 .It Fl g Ar sweepminsize
328 payload to start with when sending sweeping pings.
329 The default value is 0.
330 .It Fl h Ar sweepincrsize
331 Specify the number of bytes to increment the size of
334 each sweep when sending sweeping pings.
335 The default value is 1.
337 Suppress loopback of multicast packets.
338 This flag only applies if the ping destination is a multicast address.
339 .It Fl M Cm mask | time
348 print the netmask of the remote machine.
350 .Va net.inet.icmp.maskrepl
351 MIB variable to enable
354 .Va net.inet.icmp.maskfake
355 if you want to override the netmask in the response.
358 print the origination, reception and transmission timestamps.
360 .Va net.inet.icmp.tstamprepl
361 MIB variable to enable or disable
362 .Dv ICMP_TSTAMPREPLY .
364 Somewhat quiet output.
366 display ICMP error messages that are in response to our query messages.
369 flag was required to display such errors, but
371 displays all ICMP error messages.
372 On a busy machine, this output can be overbearing.
377 prints out any ICMP error messages caused by its own ECHO_REQUEST
386 the route buffer on returned packets.
387 Note that the IP header is only large enough for nine such routes;
390 command is usually better at determining the route packets take to a
391 particular destination.
392 If more routes come back than should, such as due to an illegal spoofed
393 packet, ping will print the route list and then truncate it at the correct
395 Many hosts ignore or discard the
399 Bypass the normal routing tables and send directly to a host on an attached
401 If the host is not on a directly-attached network, an error is returned.
402 This option can be used to ping a local host through an interface
403 that has no route through it
404 (e.g., after the interface was dropped by
407 Set the IP Time To Live for multicasted packets.
408 This flag only applies if the ping destination is a multicast address.
410 Use the specified type of service.
412 hostname or IPv4 address of the final destination node.
413 .It Ar IPv4-mcast-group
414 IPv4 multicast address of the final destination nodes.
416 .Ss Options only for IPv6 targets
417 .Bl -tag -width indent
419 Use IPv6 regardless of how the target is resolved.
421 Set socket buffer size.
425 as the next hop to the destination.
426 The gateway must be a neighbor of the sending node.
428 Generate ICMPv6 Node Information Node Addresses query, rather than echo-request.
430 must be a string constructed of the following characters.
431 .Bl -tag -width Ds -compact
433 requests unicast addresses from all of the responder's interfaces.
434 If the character is omitted,
435 only those addresses which belong to the interface which has the
436 responder's address are requests.
438 requests responder's IPv4-compatible and IPv4-mapped addresses.
440 requests responder's global-scope addresses.
442 requests responder's site-local addresses.
444 requests responder's link-local addresses.
446 requests responder's anycast addresses.
447 Without this character, the responder will return unicast addresses only.
448 With this character, the responder will return anycast addresses only.
449 Note that the specification does not specify how to get responder's
451 This is an experimental option.
454 Probe node information multicast group address
455 .Pq Li ff02::2:ffxx:xxxx .
457 must be string hostname of the target
458 (must not be a numeric IPv6 address).
459 Node information multicast group will be computed based on given
461 and will be used as the final destination.
462 Since node information multicast group is a link-local multicast group,
463 outgoing interface needs to be specified by
467 When specified twice, the address
468 .Pq Li ff02::2:xxxx:xxxx
470 The former is in RFC 4620, the latter is in an old Internet Draft
471 draft-ietf-ipngwg-icmp-name-lookup.
472 Note that KAME-derived implementations including
476 Generate ICMPv6 Node Information supported query types query,
477 rather than echo-request.
485 asks the kernel to fragment packets to fit into the minimum IPv6 MTU.
489 will suppress the behavior in the following two levels:
490 when the option is specified once, the behavior will be disabled for
492 When the option is more than once, it will be disabled for both
493 unicast and multicast packets.
497 but with old packet format based on 03 draft.
498 This option is present for backward compatibility.
504 Generate ICMPv6 Node Information DNS Name query, rather than echo-request.
510 IPv6 addresses for intermediate nodes,
511 which will be put into type 0 routing header.
513 IPv6 address of the final destination node.
515 .Ss Experimental options only for IPv6 target
516 .Bl -tag -width indent
518 Enables transport-mode IPsec encapsulated security payload.
520 Enables transport-mode IPsec authentication header.
525 for fault isolation, it should first be run on the local host, to verify
526 that the local network interface is up and running.
527 Then, hosts and gateways further and further away should be
529 Round-trip times and packet loss statistics are computed.
530 If duplicate packets are received, they are not included in the packet
531 loss calculation, although the round trip time of these packets is used
532 in calculating the round-trip time statistics.
533 When the specified number of packets have been sent
535 or if the program is terminated with a
537 a brief summary is displayed, showing the number of packets sent and
538 received, and the minimum, mean, maximum, and standard deviation of
539 the round-trip times.
549 signal, the current number of packets sent and received, and the
550 minimum, mean, maximum, and standard deviation of the round-trip times
551 will be written to the standard output.
553 This program is intended for use in network testing, measurement and
555 Because of the load it can impose on the network, it is unwise to use
557 during normal operations or from automated scripts.
558 .Sh ICMP PACKET DETAILS
559 An IP header without options is 20 bytes.
563 packet contains an additional 8 bytes worth of
565 header followed by an arbitrary amount of data.
568 is given, this indicated the size of this extra piece of data
570 Thus the amount of data received inside of an IP packet of type
573 will always be 8 bytes more than the requested data space
578 If the data space is at least eight bytes large,
580 uses the first eight bytes of this space to include a timestamp which
581 it uses in the computation of round trip times.
582 If less than eight bytes of pad are specified, no round trip times are
584 .Sh DUPLICATE AND DAMAGED PACKETS
587 utility will report duplicate and damaged packets.
588 Duplicate packets should never occur when pinging a unicast address,
589 and seem to be caused by
590 inappropriate link-level retransmissions.
591 Duplicates may occur in many situations and are rarely
593 a good sign, although the presence of low levels of duplicates may not
594 always be cause for alarm.
595 Duplicates are expected when pinging a broadcast or multicast address,
596 since they are not really duplicates but replies from different hosts
599 Damaged packets are obviously serious cause for alarm and often
600 indicate broken hardware somewhere in the
602 packet's path (in the network or in the hosts).
603 .Sh TRYING DIFFERENT DATA PATTERNS
606 layer should never treat packets differently depending on the data
607 contained in the data portion.
608 Unfortunately, data-dependent problems have been known to sneak into
609 networks and remain undetected for long periods of time.
610 In many cases the particular pattern that will have problems is something
611 that does not have sufficient
613 such as all ones or all zeros, or a pattern right at the edge, such as
616 necessarily enough to specify a data pattern of all zeros (for example)
617 on the command line because the pattern that is of interest is
618 at the data link level, and the relationship between what you type and
619 what the controllers transmit can be complicated.
621 This means that if you have a data-dependent problem you will probably
622 have to do a lot of testing to find it.
623 If you are lucky, you may manage to find a file that either
625 be sent across your network or that takes much longer to transfer than
626 other similar length files.
627 You can then examine this file for repeated patterns that you can test
635 value of an IP packet represents the maximum number of IP routers
636 that the packet can go through before being thrown away.
637 In current practice you can expect each router in the Internet to decrement
640 field by exactly one.
644 specification recommends setting the
648 packets to 64, but many systems use smaller values
654 The maximum possible value of this field is 255, and most
660 .Tn ICMP ECHO_REQUEST
662 This is why you will find you can
664 some hosts, but not reach them with
671 prints the ttl value from the packet it receives.
672 When a remote system receives a ping packet, it can do one of three things
675 field in its response:
678 Not change it; this is what
680 systems did before the
685 value in the received packet will be 255 minus the
686 number of routers in the round-trip path.
688 Set it to 255; this is what current
693 value in the received packet will be 255 minus the
694 number of routers in the path
702 Set it to some other value.
703 Some machines use the same value for
705 packets that they use for
707 packets, for example either 30 or 60.
708 Others may use completely wild values.
713 utility exits with one of the following values:
714 .Bl -tag -width indent
716 At least one response was heard from the specified
719 The transmission was successful but no responses were received.
724 The following will send ICMPv6 echo request to
726 .Bd -literal -offset indent
727 ping -6 -n dst.foo.com
730 The following will probe hostnames for all nodes on the network link attached to
735 is named the link-local all-node multicast address, and the packet would
736 reach every node on the network link.
737 .Bd -literal -offset indent
738 ping -6 -y ff02::1%wi0
741 The following will probe addresses assigned to the destination node,
743 .Bd -literal -offset indent
744 ping -6 -k agl dst.foo.com
759 .%T "Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification"
765 .%T "IPv6 Node Information Queries"
766 .%N draft-ietf-ipngwg-icmp-name-lookups-09.txt
768 .%O work in progress material
777 utility with IPv6 support first appeared in the WIDE Hydrangea IPv6
780 IPv6 and IPsec support based on the KAME Project
781 .Pq Pa http://www.kame.net/
782 stack was initially integrated into
787 utility was merged to
789 in Google Summer of Code 2019.
793 utility was written by
795 while at the US Army Ballistics
798 Many Hosts and Gateways ignore the IPv4
802 The maximum IP header length is too small for options like
804 to be completely useful.
806 not much that can be done about this, however.
808 Flood pinging is not recommended in general, and flood pinging the
809 broadcast address should only be done under very controlled conditions.
813 option is not worth much on busy hosts.
projects / FreeBSD / FreeBSD.git / blob