1 .\" Copyright (c) 1985, 1991, 1993
2 .\" The Regents of the University of California. All rights reserved.
4 .\" Redistribution and use in source and binary forms, with or without
5 .\" modification, are permitted provided that the following conditions
7 .\" 1. Redistributions of source code must retain the above copyright
8 .\" notice, this list of conditions and the following disclaimer.
9 .\" 2. Redistributions in binary form must reproduce the above copyright
10 .\" notice, this list of conditions and the following disclaimer in the
11 .\" documentation and/or other materials provided with the distribution.
12 .\" 3. Neither the name of the University nor the names of its contributors
13 .\" may be used to endorse or promote products derived from this software
14 .\" without specific prior written permission.
16 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
17 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
20 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 .\" @(#)ping.8 8.2 (Berkeley) 12/11/93
29 .\" $FreeBSD: src/sbin/ping/ping.8,v 1.54 2006/04/05 12:30:42 glebius Exp $
38 packets to network hosts
43 .Op Fl G Ar sweepmaxsize
44 .Op Fl g Ar sweepminsize
45 .Op Fl h Ar sweepincrsize
48 .Op Fl M Cm mask | time
52 .Op Fl s Ar packetsize
63 .Op Fl M Cm mask | time
67 .Op Fl s Ar packetsize
78 .No protocol Ap s mandatory
81 .Tn ICMP ECHO_RESPONSE
82 from a host or gateway.
90 and then an arbitrary number of
92 bytes used to fill out the packet.
93 The options are as follows:
94 .Bl -tag -width indent
100 character when no packet is received before the next packet
102 To cater for round-trip times that are longer than the interval
103 between transmissions, further missing packets cause a bell only
104 if the maximum number of unreceived packets has increased.
110 character in the output when any packet is received.
111 This option is ignored
112 if other format options are present.
119 If this option is not specified,
121 will operate until interrupted.
122 If this option is specified in conjunction with ping sweeps,
123 each sweep will consist of
127 Set the Don't Fragment bit.
131 option on the socket being used.
134 Outputs packets as fast as they come back or one hundred times per second,
140 is printed, while for every
142 received a backspace is printed.
143 This provides a rapid display of how many packets are being dropped.
144 Only the super-user may use this option.
146 This can be very hard on a network and should be used with caution.
148 .It Fl G Ar sweepmaxsize
149 Specify the maximum size of
151 payload when sending sweeping pings.
152 This option is required for ping sweeps.
153 .It Fl g Ar sweepminsize
156 payload to start with when sending sweeping pings.
157 The default value is 0.
158 .It Fl h Ar sweepincrsize
159 Specify the number of bytes to increment the size of
162 each sweep when sending sweeping pings.
163 The default value is 1.
165 Source multicast packets with the given interface address.
166 This flag only applies if the ping destination is a multicast address.
171 .Em between sending each packet .
172 The default is to wait for one second between each packet.
173 The wait time may be fractional, but only the super-user may specify
174 values less than 1 second.
175 This option is incompatible with the
179 Suppress loopback of multicast packets.
180 This flag only applies if the ping destination is a multicast address.
186 sends that many packets as fast as possible before falling into its normal
188 Only the super-user may use this option.
189 .It Fl M Cm mask | time
198 print the netmask of the remote machine.
200 .Va net.inet.icmp.maskrepl
201 MIB variable to enable
205 print the origination, reception and transmission timestamps.
207 Set the IP Time To Live for outgoing packets.
208 If not specified, the kernel uses the value of the
213 No attempt will be made to lookup symbolic names for host addresses.
215 Exit successfully after receiving one reply packet.
217 You may specify up to 16
219 bytes to fill out the packet you send.
220 This is useful for diagnosing data-dependent problems in a network.
223 will cause the sent packet to be filled with all
226 Somewhat quiet output.
228 display ICMP error messages that are in response to our query messages.
231 flag was required to display such errors, but
233 displays all ICMP error messages.
234 On a busy machine, this output can be overbearing.
239 prints out any ICMP error messages caused by its own ECHO_REQUEST
243 Nothing is displayed except the summary lines at startup time and
252 the route buffer on returned packets.
253 Note that the IP header is only large enough for nine such routes;
256 command is usually better at determining the route packets take to a
257 particular destination.
258 If more routes come back than should, such as due to an illegal spoofed
259 packet, ping will print the route list and then truncate it at the correct
261 Many hosts ignore or discard the
265 Bypass the normal routing tables and send directly to a host on an attached
267 If the host is not on a directly-attached network, an error is returned.
268 This option can be used to ping a local host through an interface
269 that has no route through it
270 (e.g., after the interface was dropped by
273 Use the following IP address as the source address in outgoing packets.
274 On hosts with more than one IP address, this option can be used to
275 force the source address to be something other than the IP address
276 of the interface the probe packet is sent on.
278 is not one of this machine's interface addresses, an error is
279 returned and nothing is sent.
280 .It Fl s Ar packetsize
281 Specify the number of data bytes to be sent.
282 The default is 56, which translates into 64
284 data bytes when combined
288 Only the super-user may specify values more than default.
289 This option cannot be used with ping sweeps.
291 Set the IP Time To Live for multicasted packets.
292 This flag only applies if the ping destination is a multicast address.
294 Specify a timeout, in seconds, before ping exits regardless of how
295 many packets have been received.
301 that are received are listed.
303 Time in milliseconds to wait for a reply for each packet sent.
304 If a reply arrives later, the packet is not printed as replied, but
305 considered as replied when calculating statistics.
307 Use the specified type of service.
312 for fault isolation, it should first be run on the local host, to verify
313 that the local network interface is up and running.
314 Then, hosts and gateways further and further away should be
316 Round-trip times and packet loss statistics are computed.
317 If duplicate packets are received, they are not included in the packet
318 loss calculation, although the round trip time of these packets is used
319 in calculating the round-trip time statistics.
320 When the specified number of packets have been sent
322 or if the program is terminated with a
324 a brief summary is displayed, showing the number of packets sent and
325 received, and the minimum, mean, maximum, and standard deviation of
326 the round-trip times.
336 signal, the current number of packets sent and received, and the
337 minimum, mean, and maximum of the round-trip times will be written to
338 the standard error output.
340 This program is intended for use in network testing, measurement and
342 Because of the load it can impose on the network, it is unwise to use
344 during normal operations or from automated scripts.
345 .Sh ICMP PACKET DETAILS
346 An IP header without options is 20 bytes.
350 packet contains an additional 8 bytes worth of
352 header followed by an arbitrary amount of data.
355 is given, this indicated the size of this extra piece of data
357 Thus the amount of data received inside of an IP packet of type
360 will always be 8 bytes more than the requested data space
365 If the data space is at least eight bytes large,
367 uses the first eight bytes of this space to include a timestamp which
368 it uses in the computation of round trip times.
369 If less than eight bytes of pad are specified, no round trip times are
371 .Sh DUPLICATE AND DAMAGED PACKETS
374 utility will report duplicate and damaged packets.
375 Duplicate packets should never occur when pinging a unicast address,
376 and seem to be caused by
377 inappropriate link-level retransmissions.
378 Duplicates may occur in many situations and are rarely
380 a good sign, although the presence of low levels of duplicates may not
381 always be cause for alarm.
382 Duplicates are expected when pinging a broadcast or multicast address,
383 since they are not really duplicates but replies from different hosts
386 Damaged packets are obviously serious cause for alarm and often
387 indicate broken hardware somewhere in the
389 packet's path (in the network or in the hosts).
390 .Sh TRYING DIFFERENT DATA PATTERNS
393 layer should never treat packets differently depending on the data
394 contained in the data portion.
395 Unfortunately, data-dependent problems have been known to sneak into
396 networks and remain undetected for long periods of time.
397 In many cases the particular pattern that will have problems is something
398 that does not have sufficient
400 such as all ones or all zeros, or a pattern right at the edge, such as
403 necessarily enough to specify a data pattern of all zeros (for example)
404 on the command line because the pattern that is of interest is
405 at the data link level, and the relationship between what you type and
406 what the controllers transmit can be complicated.
408 This means that if you have a data-dependent problem you will probably
409 have to do a lot of testing to find it.
410 If you are lucky, you may manage to find a file that either
412 be sent across your network or that takes much longer to transfer than
413 other similar length files.
414 You can then examine this file for repeated patterns that you can test
422 value of an IP packet represents the maximum number of IP routers
423 that the packet can go through before being thrown away.
424 In current practice you can expect each router in the Internet to decrement
427 field by exactly one.
431 specification recommends setting the
435 packets to 64, but many systems use smaller values
441 The maximum possible value of this field is 255, and most
447 .Tn ICMP ECHO_REQUEST
449 This is why you will find you can
451 some hosts, but not reach them with
458 prints the ttl value from the packet it receives.
459 When a remote system receives a ping packet, it can do one of three things
462 field in its response:
465 Not change it; this is what
467 systems did before the
472 value in the received packet will be 255 minus the
473 number of routers in the round-trip path.
475 Set it to 255; this is what current
480 value in the received packet will be 255 minus the
481 number of routers in the path
489 Set it to some other value.
490 Some machines use the same value for
492 packets that they use for
494 packets, for example either 30 or 60.
495 Others may use completely wild values.
500 utility returns an exit status of zero if at least one response was
501 heard from the specified
503 a status of two if the transmission was successful but no responses
504 were received; or another value
507 if an error occurred.
521 utility was written by
523 while at the US Army Ballistics
526 Many Hosts and Gateways ignore the
530 The maximum IP header length is too small for options like
532 to be completely useful.
534 not much that can be done about this, however.
536 Flood pinging is not recommended in general, and flood pinging the
537 broadcast address should only be done under very controlled conditions.
541 option is not worth much on busy hosts.
projects / dragonfly.git / blob