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28 .\" @(#)ping.8 8.2 (Berkeley) 12/11/93
40 packets to network hosts
44 .Op Fl .\& Ns Ar chars
47 .Op Fl G Ar sweepmaxsize
48 .Op Fl g Ar sweepminsize
49 .Op Fl h Ar sweepincrsize
52 .Op Fl M Cm mask | time
57 .Op Fl s Ar packetsize
63 .Op Fl 4AaDdfHLnoQqRrv
64 .Op Fl .\& Ns Ar chars
70 .Op Fl M Cm mask | time
75 .Op Fl s Ar packetsize
82 .Op Fl 6AaDdEfHNnOoquvYyZ
83 .Op Fl .\& Ns Ar chars
94 .Op Fl S Ar sourceaddr
95 .Op Fl s Ar packetsize
103 utility invoked with an IPv4 target
106 .Ar IPv4-mcast-group )
109 .No protocol Ap s mandatory
111 datagram to elicit an
113 from a host or gateway.
119 header, followed by a
121 and then an arbitrary number of
123 bytes used to fill out the packet.
125 When invoked with an IPv6 target
131 datagram to elicit an
134 datagrams have an IPv6 header and
136 header formatted as documented in RFC 2463.
138 When invoked with a hostname, the version to which the target is resolved first
140 In that case, the options and arguments used must be valid for the specific IP
144 If the target is resolved to both IPv4 and IPv6, the specific IP version can be
149 options, respectively.
150 For backwards-compatibility, ICMPv6 can also be selected by invoking the binary
153 .Ss Options common to both IPv4 and IPv6 targets
154 .Bl -tag -width indent
155 .It Fl .\& Ns Ar chars
156 By default, for every
160 is printed, while for every
162 received, a backspace is printed.
163 This option takes an optional string argument listing characters
164 that will be printed one by one in the provided order
165 instead of the default period.
168 .Bd -literal -offset indent
169 ping -.0123456789 freebsd.org
176 character when no packet is received before the next packet
178 To cater for round-trip times that are longer than the interval
179 between transmissions, further missing packets cause a bell only
180 if the maximum number of unreceived packets has increased.
186 character in the output when any packet is received.
188 Add an 802.1p Ethernet Priority Code Point when sending a packet.
189 0..7 uses that specific PCP, -1 uses the interface default PCP (or none).
196 If this option is not specified,
198 will operate until interrupted.
200 For an IPv4 target, if this option is specified in conjunction with ping sweeps,
201 each sweep will consist of
205 Disable fragmentation.
209 option on the socket being used.
212 Outputs packets as fast as they come back or one hundred times per second,
216 to print a period for every
218 sent and a backspace for every
221 This provides a rapid display of how many packets are being dropped.
222 Only the super-user may use this option.
224 This can be very hard on a network and should be used with caution.
228 Try to do a reverse DNS lookup when displaying addresses.
229 This is the opposite of the
235 is an IP address indentifying an interface from which the packets will be sent.
236 This flag applies only if the ping target is a multicast address.
240 is a name of an interface (e.g., `em0') from which the packets will be sent.
241 This flag applies if the ping target is a multicast address, or
242 link-local/site-local unicast address.
247 .Em between sending each packet .
248 The default is to wait for one second between each packet.
249 The wait time may be fractional, but only the super-user may specify
250 values less than 1 second.
251 This option is incompatible with the
259 sends that many packets as fast as possible before falling into its normal
261 Only the super-user may use this option.
263 For an IPv4 target, set the IP Time To Live for outgoing packets.
264 If not specified, the kernel uses the value of the
268 For an IPv6 target, set the IPv6 hoplimit.
271 No attempt will be made to lookup symbolic names for host addresses.
272 This is the opposite of
274 and it is the default behavior.
276 Exit successfully after receiving one reply packet.
279 specifies IPsec policy for the ping session.
280 For details please refer to
283 .Xr ipsec_set_policy 3 .
285 You may specify up to 16
287 bytes to fill out the packet you send.
288 This is useful for diagnosing data-dependent problems in a network.
291 will cause the sent packet to be filled with all
295 Nothing is displayed except the summary lines at startup time and
298 Use the following IP address as the source address in outgoing packets.
299 On hosts with more than one IP address, this option can be used to
300 force the source address to be something other than the IP address
301 of the interface the probe packet is sent on.
303 For IPv4, if the IP address is not one of this machine's interface
304 addresses, an error is returned and nothing is sent.
306 For IPv6, the source address must be one of the unicast addresses of
307 the sending node, and must be numeric.
308 .It Fl s Ar packetsize
309 Specify the number of data bytes to be sent.
310 The default is 56, which translates into 64
312 data bytes when combined
317 For IPv4, only the super-user may specify values more than default.
318 This option cannot be used with ping sweeps.
320 For IPv6, you may need to specify
322 as well to extend socket buffer size.
324 Specify a timeout, in seconds, before ping exits regardless of how
325 many packets have been received.
331 that are received are listed.
333 Time in milliseconds to wait for a reply for each packet sent.
334 If a reply arrives later, the packet is not printed as replied, but
335 considered as replied when calculating statistics.
337 .Ss Options only for IPv4 targets
338 .Bl -tag -width indent
340 Use IPv4 regardless of how the target is resolved.
341 .It Fl G Ar sweepmaxsize
342 Specify the maximum size of
344 payload when sending sweeping pings.
345 This option is required for ping sweeps.
346 .It Fl g Ar sweepminsize
349 payload to start with when sending sweeping pings.
350 The default value is 0.
351 .It Fl h Ar sweepincrsize
352 Specify the number of bytes to increment the size of
355 each sweep when sending sweeping pings.
356 The default value is 1.
358 Suppress loopback of multicast packets.
359 This flag only applies if the ping destination is a multicast address.
360 .It Fl M Cm mask | time
369 print the netmask of the remote machine.
371 .Va net.inet.icmp.maskrepl
372 MIB variable to enable
375 .Va net.inet.icmp.maskfake
376 if you want to override the netmask in the response.
379 print the origination, reception and transmission timestamps.
381 .Va net.inet.icmp.tstamprepl
382 MIB variable to enable or disable
383 .Dv ICMP_TSTAMPREPLY .
385 Somewhat quiet output.
387 display ICMP error messages that are in response to our query messages.
390 flag was required to display such errors, but
392 displays all ICMP error messages.
393 On a busy machine, this output can be overbearing.
398 prints out any ICMP error messages caused by its own ECHO_REQUEST
407 the route buffer on returned packets.
408 Note that the IP header is only large enough for nine such routes;
411 command is usually better at determining the route packets take to a
412 particular destination.
413 If more routes come back than should, such as due to an illegal spoofed
414 packet, ping will print the route list and then truncate it at the correct
416 Many hosts ignore or discard the
420 Bypass the normal routing tables and send directly to a host on an attached
422 If the host is not on a directly-attached network, an error is returned.
423 This option can be used to ping a local host through an interface
424 that has no route through it
425 (e.g., after the interface was dropped by
428 Set the IP Time To Live for multicasted packets.
429 This flag only applies if the ping destination is a multicast address.
431 Use the specified type of service.
433 hostname or IPv4 address of the final destination node.
434 .It Ar IPv4-mcast-group
435 IPv4 multicast address of the final destination nodes.
437 .Ss Options only for IPv6 targets
438 .Bl -tag -width indent
440 Use IPv6 regardless of how the target is resolved.
442 Set socket buffer size.
446 as the next hop to the destination.
447 The gateway must be a neighbor of the sending node.
449 Generate ICMPv6 Node Information Node Addresses query, rather than echo-request.
451 must be a string constructed of the following characters.
452 .Bl -tag -width Ds -compact
454 requests unicast addresses from all of the responder's interfaces.
455 If the character is omitted,
456 only those addresses which belong to the interface which has the
457 responder's address are requests.
459 requests responder's IPv4-compatible and IPv4-mapped addresses.
461 requests responder's global-scope addresses.
463 requests responder's site-local addresses.
465 requests responder's link-local addresses.
467 requests responder's anycast addresses.
468 Without this character, the responder will return unicast addresses only.
469 With this character, the responder will return anycast addresses only.
470 Note that the specification does not specify how to get responder's
472 This is an experimental option.
475 Probe node information multicast group address
476 .Pq Li ff02::2:ffxx:xxxx .
478 must be string hostname of the target
479 (must not be a numeric IPv6 address).
480 Node information multicast group will be computed based on given
482 and will be used as the final destination.
483 Since node information multicast group is a link-local multicast group,
484 outgoing interface needs to be specified by
488 When specified twice, the address
489 .Pq Li ff02::2:xxxx:xxxx
491 The former is in RFC 4620, the latter is in an old Internet Draft
492 draft-ietf-ipngwg-icmp-name-lookup.
493 Note that KAME-derived implementations including
497 Generate ICMPv6 Node Information supported query types query,
498 rather than echo-request.
506 asks the kernel to fragment packets to fit into the minimum IPv6 MTU.
510 will suppress the behavior in the following two levels:
511 when the option is specified once, the behavior will be disabled for
513 When the option is more than once, it will be disabled for both
514 unicast and multicast packets.
518 but with old packet format based on 03 draft.
519 This option is present for backward compatibility.
525 Generate ICMPv6 Node Information DNS Name query, rather than echo-request.
531 IPv6 addresses for intermediate nodes,
532 which will be put into type 0 routing header.
534 IPv6 address of the final destination node.
536 .Ss Experimental options only for IPv6 target
537 .Bl -tag -width indent
539 Enables transport-mode IPsec encapsulated security payload.
541 Enables transport-mode IPsec authentication header.
546 for fault isolation, it should first be run on the local host, to verify
547 that the local network interface is up and running.
548 Then, hosts and gateways further and further away should be
550 Round-trip times and packet loss statistics are computed.
551 If duplicate packets are received, they are not included in the packet
552 loss calculation, although the round trip time of these packets is used
553 in calculating the round-trip time statistics.
554 When the specified number of packets have been sent
556 or if the program is terminated with a
558 a brief summary is displayed, showing the number of packets sent and
559 received, and the minimum, mean, maximum, and standard deviation of
560 the round-trip times.
570 signal, the current number of packets sent and received, and the
571 minimum, mean, maximum, and standard deviation of the round-trip times
572 will be written to the standard output.
574 This program is intended for use in network testing, measurement and
576 Because of the load it can impose on the network, it is unwise to use
578 during normal operations or from automated scripts.
579 .Sh ICMP PACKET DETAILS
580 An IP header without options is 20 bytes.
584 packet contains an additional 8 bytes worth of
586 header followed by an arbitrary amount of data.
589 is given, this indicated the size of this extra piece of data
591 Thus the amount of data received inside of an IP packet of type
594 will always be 8 bytes more than the requested data space
599 If the data space is at least eight bytes large,
601 uses the first eight bytes of this space to include a timestamp which
602 it uses in the computation of round trip times.
603 If less than eight bytes of pad are specified, no round trip times are
605 .Sh DUPLICATE AND DAMAGED PACKETS
608 utility will report duplicate and damaged packets.
609 Duplicate packets should never occur when pinging a unicast address,
610 and seem to be caused by
611 inappropriate link-level retransmissions.
612 Duplicates may occur in many situations and are rarely
614 a good sign, although the presence of low levels of duplicates may not
615 always be cause for alarm.
616 Duplicates are expected when pinging a broadcast or multicast address,
617 since they are not really duplicates but replies from different hosts
620 Damaged packets are obviously serious cause for alarm and often
621 indicate broken hardware somewhere in the
623 packet's path (in the network or in the hosts).
624 .Sh TRYING DIFFERENT DATA PATTERNS
627 layer should never treat packets differently depending on the data
628 contained in the data portion.
629 Unfortunately, data-dependent problems have been known to sneak into
630 networks and remain undetected for long periods of time.
631 In many cases the particular pattern that will have problems is something
632 that does not have sufficient
634 such as all ones or all zeros, or a pattern right at the edge, such as
637 necessarily enough to specify a data pattern of all zeros (for example)
638 on the command line because the pattern that is of interest is
639 at the data link level, and the relationship between what you type and
640 what the controllers transmit can be complicated.
642 This means that if you have a data-dependent problem you will probably
643 have to do a lot of testing to find it.
644 If you are lucky, you may manage to find a file that either
646 be sent across your network or that takes much longer to transfer than
647 other similar length files.
648 You can then examine this file for repeated patterns that you can test
656 value of an IP packet represents the maximum number of IP routers
657 that the packet can go through before being thrown away.
658 In current practice you can expect each router in the Internet to decrement
661 field by exactly one.
665 specification recommends setting the
671 The maximum possible value of this field is 255, and some
679 This is why you will find you can
681 some hosts, but not reach them with
688 prints the ttl value from the packet it receives.
689 When a remote system receives a ping packet, it can do one of three things
692 field in its response:
695 Not change it; this is what
697 systems did before the
702 value in the received packet will be 255 minus the
703 number of routers in the round-trip path.
705 Set it to 64; this is what current
710 value in the received packet will be 64 minus the
711 number of routers in the path
719 Set it to some other value.
720 Some machines use the same value for
722 packets that they use for
724 packets, for example either 30 or 60.
725 Others may use completely wild values.
730 utility exits with one of the following values:
731 .Bl -tag -width indent
733 At least one response was heard from the specified
736 The transmission was successful but no responses were received.
741 The following will send ICMPv6 echo request to
742 .Li dst.example.com .
743 .Bd -literal -offset indent
744 ping -6 -n dst.example.com
747 The following will probe hostnames for all nodes on the network link attached to
752 is named the link-local all-node multicast address, and the packet would
753 reach every node on the network link.
754 .Bd -literal -offset indent
755 ping -6 -y ff02::1%wi0
758 The following will probe addresses assigned to the destination node,
759 .Li dst.example.com .
760 .Bd -literal -offset indent
761 ping -6 -k agl dst.example.com
776 .%T "Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification"
782 .%T "IPv6 Node Information Queries"
783 .%N draft-ietf-ipngwg-icmp-name-lookups-09.txt
785 .%O work in progress material
794 utility with IPv6 support first appeared in the WIDE Hydrangea IPv6
797 IPv6 and IPsec support based on the KAME Project
798 .Pq Pa https://www.kame.net/
799 stack was initially integrated into
804 utility was merged to
806 in Google Summer of Code 2019.
810 utility was written by
812 while at the US Army Ballistics
815 Many Hosts and Gateways ignore the IPv4
819 The maximum IP header length is too small for options like
821 to be completely useful.
823 not much that can be done about this, however.
825 Flood pinging is not recommended in general, and flood pinging the
826 broadcast address should only be done under very controlled conditions.
830 option is not worth much on busy hosts.
projects / FreeBSD / FreeBSD.git / blob