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PING6(8)                  BSD System Manager's Manual                 PING6(8)

NAME
     ping6 -- send ICMPv6 ECHO_REQUEST packets to network hosts

SYNOPSIS
     ping6 [-CDdfHmnNoqtvwW] [-a addrtype] [-b bufsiz] [-B boundif] [-c count] [-g gateway] [-h hoplimit]
           [-I interface] [-i wait] [-l preload] [-P policy] [-p pattern] [-S sourceaddr] [-s packetsize]
           [-z tclass] [hops ...] host

DESCRIPTION
     The ping6 utility uses the ICMPv6 protocol's mandatory ICMP6_ECHO_REQUEST datagram to elicit an
     ICMP6_ECHO_REPLY from a host or gateway.  ICMP6_ECHO_REQUEST datagrams (``pings'') have an IPv6 header,
     and ICMPv6 header formatted as documented in RFC2463.  The options are as follows:

     -a addrtype
             Generate ICMPv6 Node Information Node Addresses query, rather than echo-request.  addrtype must
             be a string constructed of the following characters.
             a       requests unicast addresses from all of the responder's interfaces.  If the character is
                     omitted, only those addresses which belong to the interface which has the responder's
                     address are requests.
             c       requests responder's IPv4-compatible and IPv4-mapped addresses.
             g       requests responder's global-scope addresses.
             s       requests responder's site-local addresses.
             l       requests responder's link-local addresses.
             A       requests responder's anycast addresses.  Without this character, the responder will
                     return unicast addresses only.  With this character, the responder will return anycast
                     addresses only.  Note that the specification does not specify how to get responder's
                     anycast addresses.  This is an experimental option.

     -b bufsiz
             Set socket buffer size.

     -B boundif
             Bind the socket to interface boundif for sending.

     -C      Prohibit the socket from using the cellular network interface.

     -c count
             Stop after sending (and receiving) count ECHO_RESPONSE packets.

     -D      Disable IPv6 fragmentation.

     -d      Set the SO_DEBUG option on the socket being used.

     -f      Flood ping.  Outputs packets as fast as they come back or one hundred times per second, which-ever whichever
             ever is more.  For every ECHO_REQUEST sent a period ``.'' is printed, while for every
             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.  This can be very hard on a net-work network
             work and should be used with caution.

     -g gateway
             Specifies to use gateway as the next hop to the destination.  The gateway must be a neighbor of
             the sending node.

     -H      Specifies to try reverse-lookup of IPv6 addresses.  The ping6 utility does not try reverse-lookup reverselookup
             lookup unless the option is specified.

     -h hoplimit
             Set the IPv6 hoplimit.

     -I interface
             Source packets with the given interface address.  This flag applies if the ping destination is
             a multicast address, or link-local/site-local unicast address.

     -i wait
             Wait wait seconds between sending each packet.  The default is to wait for one second between
             each packet.  The wait time may be fractional, but only the super-user may specify values less
             than 0.1 second.  This option is incompatible with the -f option.

     -l preload
             If preload is specified, ping6 sends that many packets as fast as possible before falling into
             its normal mode of behavior.  Only the super-user may use this option.

     -m      By default, ping6 asks the kernel to fragment packets to fit into the minimum IPv6 MTU.  The -m
             option 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 more than once, it
             will be disabled for both unicast and multicast packets.

     -n      Numeric output only.  No attempt will be made to lookup symbolic names from addresses in the
             reply.

     -N      Probe node information multicast group (ff02::2:xxxx:xxxx).  host must be string hostname of
             the target (must not be a numeric IPv6 address).  Node information multicast group will be com-puted computed
             puted based on given host, and will be used as the final destination.  Since node information
             multicast group is a link-local multicast group, outgoing interface needs to be specified by -I
             option.

     -o      Exit successfully after receiving one reply packet.

     -p pattern
             You may specify up to 16 ``pad'' bytes to fill out the packet you send.  This is useful for
             diagnosing data-dependent problems in a network.  For example, ``-p ff'' will cause the sent
             packet to be filled with all ones.

     -P policy
             policy specifies IPsec policy to be used for the probe.

     -q      Quiet output.  Nothing is displayed except the summary lines at startup time and when finished.

     -r      Audible.  Include a bell (ASCII 0x07) character in the output when any packet is received.

     -R      Audible.  Output a bell (ASCII 0x07) character 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.

     -S 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.

     -s 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.  You may need to specify -b
             as well to extend socket buffer size.

     -t      Generate ICMPv6 Node Information supported query types query, rather than echo-request.  -s has
             no effect if -t is specified.

     -v      Verbose output.  ICMP packets other than ECHO_RESPONSE that are received are listed.

     -w      Generate ICMPv6 Node Information DNS Name query, rather than echo-request.  -s has no effect if
             -w is specified.

     -W      Same as -w, but with old packet format based on 03 draft.  This option is present for backward
             compatibility.  -s has no effect if -w is specified.

     -z tclass
             Use the specified traffic class.

     hops    IPv6 addresses for intermediate nodes, which will be put into type 0 routing header.

     host    IPv6 address of the final destination node.

     When using ping6 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 should be
     ``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 (and received) or if the program is terminated with a SIGINT, a brief summary is dis-played, displayed,
     played, showing the number of packets sent and received, and the minimum, mean, maximum, and standard
     deviation of the round-trip times.

     If ping6 receives a SIGINFO (see the status argument for stty(1)) signal, the current number of packets
     sent and received, and the minimum, mean, maximum, and standard deviation of the round-trip times will
     be written to the standard output in the same format as the standard completion message.

     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 ping6 during normal operations or from automated
     scripts.

DUPLICATE AND DAMAGED PACKETS
     The ping6 utility 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.  Dupli-cates Duplicates
     cates may occur in many situations and are rarely (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 broad-cast broadcast
     cast or multicast address, since they are not really duplicates but replies from different hosts to the
     same request.

     Damaged packets are obviously serious cause for alarm and often indicate broken hardware somewhere in
     the ping6 packet's path (in the network or in the hosts).

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 ``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 you type and what the controllers transmit can be complicated.

     This means that if you have a data-dependent problem you will probably have to do a lot of testing to
     find it.  If you are lucky, you may manage to find a file that either cannot be sent across your net-work network
     work or that takes much longer to transfer than other similar length files.  You can then examine this
     file for repeated patterns that you can test using the -p option of ping6.

EXIT STATUS
     The ping6 utility returns 0 on success (the host is alive), 2 if the transmission was successful but no
     responses were received, any other non-zero value if the arguments are incorrect or another error has
     occurred.

EXAMPLES
     Normally, ping6 works just like ping(8) would work; the following will send ICMPv6 echo request to
     dst.foo.com.

           ping6 -n dst.foo.com

     The following will probe hostnames for all nodes on the network link attached to wi0 interface.  The
     address ff02::1 is named the link-local all-node multicast address, and the packet would reach every
     node on the network link.

           ping6 -w ff02::1%wi0

     The following will probe addresses assigned to the destination node, dst.foo.com.

           ping6 -a agl dst.foo.com

SEE ALSO
     netstat(1), icmp6(4), inet6(4), ip6(4), ifconfig(8), ping(8), routed(8), traceroute(8), traceroute6(8)

     A. Conta and S. Deering, Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6
     (IPv6) Specification, RFC2463, December 1998.

     Matt Crawford, IPv6 Node Information Queries, draft-ietf-ipngwg-icmp-name-lookups-09.txt, May 2002,
     work in progress material.

HISTORY
     The ping(8) utility appeared in 4.3BSD.  The ping6 utility with IPv6 support first appeared in the WIDE
     Hydrangea IPv6 protocol stack kit.

     IPv6 and IPsec support based on the KAME Project (http://www.kame.net/) stack was initially integrated
     into FreeBSD 4.0.

BUGS
     The ping6 utility is intentionally separate from ping(8).

     There have been many discussions on why we separate ping6 and ping(8).  Some people argued that it
     would be more convenient to uniform the ping command for both IPv4 and IPv6.  The followings are an
     answer to the request.

     From a developer's point of view: since the underling raw sockets API is totally different between IPv4
     and IPv6, we would end up having two types of code base.  There would actually be less benefit to uni-form uniform
     form the two commands into a single command from the developer's standpoint.

     From an operator's point of view: unlike ordinary network applications like remote login tools, we are
     usually aware of address family when using network management tools.  We do not just want to know the
     reachability to the host, but want to know the reachability to the host via a particular network proto-col protocol
     col such as IPv6.  Thus, even if we had a unified ping(8) command for both IPv4 and IPv6, we would usu-ally usually
     ally type a -6 or -4 option (or something like those) to specify the particular address family.  This
     essentially means that we have two different commands.

BSD                             March 29, 2013                             BSD

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