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

NAME
     ping6 - send ICMPv6 ECHO_REQUEST packets to network hosts

SYNOPSIS
     ping6 [-dEefHmNnqtvWw] [-a addrtype] [-b bufsiz] [-c count] [-g gateway]
           [-h hoplimit] [-I interface] [-i wait] [-l preload] [-p pattern]
           [-S sourceaddr] [-s packetsize] [hops ...] host

DESCRIPTION
     ping6 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 RFC 2463.  The options are as follows:

     -a addrtype
             Generate an ICMPv6 Node Information Node Addresses query, rather
             than an echo-request.  addrtype must be a string constructed of
             the following characters:

             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 the responder's anycast addresses.
                     This is an experimental option.
             a       Requests unicast addresses from all of the responder's
                     interfaces.  If the character is omitted, only those ad-
                     dresses which belong to the interface which has the re-
                     sponder's address are requests.
             c       Requests responder's IPv4-compatible and IPv4-mapped ad-
                     dresses.
             g       Requests responder's global-scope addresses.
             l       Requests responder's link-local addresses.
             s       Requests responder's site-local addresses.

     -b bufsiz
             Set the socket buffer size.

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

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

     -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.

     -e      Emit an audible beep (by sending an ASCII BEL character to the
             standard error output) after each non-duplicate response is re-
             ceived.  This option is disabled for flood pings.

     -f      Flood ping.  Outputs packets as fast as they come back or one
             hundred times per second, whichever 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 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
             command does not try reverse-lookup unless the option is speci-
             fied.

     -h hoplimit
             Set the IPv6 hoplimit.

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

     -i wait
             Wait wait seconds between sending each packet.  The default is to
             wait for one second between each packet.  This option is incom-
             patible 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.  -m will suppress the behavior in the fol-
             lowing two levels: when the option is specified once, the behav-
             ior will be disabled for unicast packets.  When the option is
             specified more than once, it will be disabled for both unicast
             and multicast packets.

     -N      Probe the node information multicast group (ff02::2:xxxx:xxxx).
             host must be the hostname of the target (i.e. it must not be a
             numeric IPv6 address).  The node information multicast group is
             computed based on the given host, and is used as the final desti-
             nation.  Since the node information multicast group is a link-lo-
             cal multicast group, the outgoing interface needs to be specified
             using the -I option.

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

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

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

     -S sourceaddr
             Specifies the source address of request packets.  The source ad-
             dress 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.  It may also be necessary to
             specify -b to extend the socket buffer size.

             This option is ignored if any of the flags [-tWw] are specified.

     -t      Generate an ICMPv6 Node Information query, rather than echo-re-
             quest.  -s has no effect if this option is specified.

     -v      Verbose output.  All ICMP packets that are received are listed.

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

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

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

     host    The 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 can 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, al-
     though 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 displayed, showing the number of packets sent and re-
     ceived, and the minimum, maximum, mean, and standard deviation of the
     round-trip times.

     This program is intended for use in network testing, measurement, and
     management.  Because of the load it can impose on the network, it is un-
     wise to use ping6 during normal operations or from automated scripts.

     ping6 exits 0 if at least one reply is received, and >0 if no reply is
     received or an error occurred.

DUPLICATE AND DAMAGED PACKETS
     ping6 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 (if ever) a good sign, although the pres-
     ence of low levels of duplicates may not always be cause for alarm.  Du-
     plicates are expected when pinging a broadcast 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 is typed and what the controllers transmit can be complicated.

     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 -p option.

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 at-
     tached to the 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), route6d(8),
     traceroute6(8)

     A. Conta and S. Deering, Internet Control Message Protocol (ICMPv6) for
     the Internet Protocol Version 6 (IPv6) Specification, RFC 2463, 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) command first appeared in 4.3BSD.  The ping6 command with
     IPv6 support first appeared in the WIDE Hydrangea IPv6 protocol stack
     kit.

BUGS
     ping6 is intentionally separate from ping(8).

OpenBSD 4.7                      June 1, 2009                                4
