.\" $OpenBSD: ping6.8,v 1.60 2015/10/25 14:43:48 florian Exp $ .\" $KAME: ping6.8,v 1.57 2002/05/26 13:18:25 itojun Exp $ .\" .\" Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. Neither the name of the project nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .Dd $Mdocdate: October 25 2015 $ .Dt PING6 8 .Os .Sh NAME .Nm ping6 .Nd send ICMPv6 ECHO_REQUEST packets to network hosts .Sh SYNOPSIS .Nm ping6 .Op Fl dEefHLmnqv .Op Fl c Ar count .Op Fl h Ar hoplimit .Op Fl I Ar sourceaddr .Op Fl i Ar wait .Op Fl l Ar preload .Op Fl p Ar pattern .Op Fl s Ar packetsize .Op Fl V Ar rtable .Op Fl w Ar maxwait .Ar host .Sh DESCRIPTION .Nm uses the ICMPv6 protocol's mandatory .Dv ICMP6_ECHO_REQUEST datagram to elicit an .Dv ICMP6_ECHO_REPLY from a host or gateway. .Dv ICMP6_ECHO_REQUEST datagrams .Pq Dq pings have an IPv6 header, followed by an ICMPv6 header formatted as documented in RFC 4443. The options are as follows: .Bl -tag -width Ds .It Fl c Ar count Stop after sending .Pq and receiving .Ar count .Dv ECHO_RESPONSE packets. If .Ar count is 0, send an unlimited number of packets. .It Fl d Set the .Dv SO_DEBUG option on the socket being used. .It Fl E Emit an audible beep (by sending an ASCII BEL character to the standard error output) when no packet is received before the next packet is transmitted. To cater for round-trip times that are longer than the interval between transmissions, further missing packets cause a bell only if the maximum number of unreceived packets has increased. This option is disabled for flood pings. .It Fl e Emit an audible beep (by sending an ASCII BEL character to the standard error output) after each non-duplicate response is received. This option is disabled for flood pings. .It Fl f Flood ping. Outputs packets as fast as they come back or one hundred times per second, whichever is more. For every .Dv ECHO_REQUEST sent a period .Pq Sq \&. is printed, while for every .Dv ECHO_REPLY received a backspace is printed. This provides a rapid display of how many packets are being dropped. Only the super-user may use this option. .Bf -emphasis This can be very hard on a network and should be used with caution. .Ef .It Fl H Specifies to try reverse-lookup of IPv6 addresses. The .Nm command does not try reverse-lookup unless the option is specified. .It Fl h Ar hoplimit Set the IPv6 hoplimit. .It Fl I Ar sourceaddr Specifies the source address of request packets. The source address must be one of the unicast addresses of the sending node, and must be numeric. .It Fl i Ar wait Wait .Ar wait seconds .Em between sending each packet . The default is to wait for one second between each packet. This option is incompatible with the .Fl f option. .It Fl L Disable the loopback, so the transmitting host doesn't see ICMP requests. For multicast pings. .It Fl l Ar preload If .Ar preload is specified, .Nm sends that many packets as fast as possible before falling into its normal mode of behavior. Only the super-user may use this option. .It Fl m By default, .Nm asks the kernel to fragment packets to fit into the minimum IPv6 MTU. .Fl m will suppress the behavior in the following two levels: when the option is specified once, the behavior will be disabled for unicast packets. When the option is specified more than once, it will be disabled for both unicast and multicast packets. .It Fl n Numeric output only. No attempt will be made to look up symbolic names from addresses in the reply. .It Fl p Ar pattern Up to 16 .Dq pad bytes may be specified to fill out the packet sent. This is useful for diagnosing data-dependent problems in a network. For example, .Dq -p ff will cause the packet sent to be filled with all ones. .\" new ipsec .\".It Fl P Ar policy .\".Ar policy .\"specifies IPsec policy to be used for the probe. .It Fl q Quiet output. Nothing is displayed except the summary lines at startup time and when finished. .\".It Fl R .\"Make the kernel believe that the target .\".Ar host .\".Po .\"or the first .\".Ar hop .\"if you specify .\".Ar hops .\".Pc .\"is reachable, by injecting upper-layer reachability confirmation hint. .\"The option is meaningful only if the target .\".Ar host .\".Pq or the first hop .\"is a neighbor. .It Fl s Ar packetsize Specifies the number of data bytes to be sent. The default is 56, which translates into 64 ICMP data bytes when combined with the 8 bytes of ICMP header data. .Pp This option is ignored if any of the flags .Op Fl tWw are specified. .It Fl V Ar rtable Set the routing table to be used for outgoing packets. .It Fl v Verbose output. All ICMP packets that are received are listed. .It Fl w Ar maxwait Specifies the maximum number of seconds to wait for responses after the last request has been sent. The default is 10. .El .Pp When using .Nm for fault isolation, it should first be run on the local host, to verify that the local network interface is up and running. Then hosts and gateways further and further away can be .Dq pinged . Round-trip times and packet loss statistics are computed. If duplicate packets are received, they are not included in the packet loss calculation, although the round trip time of these packets is used in calculating the round-trip time statistics. When the specified number of packets have been sent .Pq and received or if the program is terminated with a .Dv SIGINT , a brief summary is displayed, showing the number of packets sent and received, and the minimum, maximum, mean, and standard deviation of the round-trip times. .Pp This program is intended for use in network testing, measurement, and management. Because of the load it can impose on the network, it is unwise to use .Nm during normal operations or from automated scripts. .\" .Sh ICMP PACKET DETAILS .\" An IP header without options is 20 bytes. .\" An .\" .Tn ICMP .\" .Tn ECHO_REQUEST .\" packet contains an additional 8 bytes worth of .\" .Tn ICMP .\" header followed by an arbitrary amount of data. .\" When a .\" .Ar packetsize .\" is given, this indicated the size of this extra piece of data .\" .Pq the default is 56 . .\" Thus the amount of data received inside of an IP packet of type .\" .Tn ICMP .\" .Tn ECHO_REPLY .\" will always be 8 bytes more than the requested data space .\" .Pq the Tn ICMP header . .\" .Pp .\" If the data space is at least eight bytes large, .\" .Nm .\" uses the first eight bytes of this space to include a timestamp which .\" it uses in the computation of round trip times. .\" If less than eight bytes of pad are specified, no round trip times are .\" given. .Sh DUPLICATE AND DAMAGED PACKETS .Nm will report duplicate and damaged packets. Duplicate packets should never occur when pinging a unicast address, and seem to be caused by inappropriate link-level retransmissions. Duplicates may occur in many situations and are rarely .Pq if ever a good sign, although the presence of low levels of duplicates may not always be cause for alarm. Duplicates are expected when pinging a broadcast or multicast address, since they are not really duplicates but replies from different hosts to the same request. .Pp Damaged packets are obviously serious cause for alarm and often indicate broken hardware somewhere in the .Nm packet's path .Pq in the network or in the hosts . .Sh TRYING DIFFERENT DATA PATTERNS The (inter)network layer should never treat packets differently depending on the data contained in the data portion. Unfortunately, data-dependent problems have been known to sneak into networks and remain undetected for long periods of time. In many cases the particular pattern that will have problems is something that does not have sufficient .Dq transitions , such as all ones or all zeros, or a pattern right at the edge, such as almost all zeros. It is not necessarily enough to specify a data pattern of all zeros (for example) on the command line because the pattern that is of interest is at the data link level, and the relationship between what is typed and what the controllers transmit can be complicated. .Pp This means that if there is a data-dependent problem, a lot of testing will probably have to be done to find it. It may be possible to find a file that either cannot be sent across the network or that takes much longer to transfer than other similar length files. This file can then be examined for repeated patterns that can be tested using the .Fl p option. .Sh EXIT STATUS .Nm exits 0 if at least one reply is received, and \*(Gt0 if no reply is received or an error occurred. .Sh EXAMPLES Normally, .Nm works just like .Xr ping 8 would work; the following will send ICMPv6 echo requests to dst.foo.com: .Bd -literal -offset indent $ ping6 -n dst.foo.com .Ed .Pp The following will send ICMPv6 echo requests to the link-local all-node multicast address. The packet reaches all nodes on the network link attached to the wi0 interface. .Bd -literal -offset indent $ ping6 ff02::1%wi0 .Ed .Sh SEE ALSO .Xr netstat 1 , .Xr icmp6 4 , .Xr inet6 4 , .Xr ip6 4 , .Xr ifconfig 8 , .Xr ping 8 , .Xr route6d 8 , .Xr traceroute6 8 .Sh STANDARDS .Rs .%A A. Conta .%A S. Deering .%A M. Gupta .%D March 2006 .%R RFC 4443 .%T "Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification" .Re .Sh HISTORY The .Xr ping 8 command first appeared in .Bx 4.3 . The .Nm command with IPv6 support first appeared in the WIDE Hydrangea IPv6 protocol stack kit. .Sh BUGS .\" except for bsdi .Nm is intentionally separate from .Xr ping 8 .