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NAME    [Toc]    [Back]

     ping6 - send ICMPv6 ECHO_REQUEST packets to network hosts

SYNOPSIS    [Toc]    [Back]

     ping6 [-dfHnNqRtvwW] [-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    [Toc]    [Back]

     ping6 uses the ICMPv6  protocol's  mandatory  ICMP6_ECHO_REQUEST datagram to
     elicit   an   ICMP6_ECHO_REPLY   from  a  host  or  gateway.
     datagrams (``pings'') have an IPv6 header, and ICMPv6 header
formatted as
     documented in RFC 2463.  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
                     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
                     only.  With this  character,  the  responder
will return
                     anycast addresses only.  Note that the specification does
                     not specify how to get  responder's  anycast
                     This is an experimental option.

     -b bufsiz
             Set 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.

     -f      Flood ping.  Outputs packets as fast  as  they  come
back or one
             hundred  times  per  second, whichever is more.  For
             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 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.   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.

     -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
             based  on  given host, and will be used as the final
             Since node information multicast group is a link-local multicast
             group,  outgoing  interface needs to be specified by
-I option.

     -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.

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

     -R      Make the kernel believe that the target host (or the
first hop if
             you  specify hops) is reachable, by injecting upperlayer reachability
 confirmation hint.  The option is  meaningful
only if the
             target host (or the first hop) is a neighbor.

     -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

     -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.

     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
     Then, hosts and gateways further and further away should  be
     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 displayed, showing the number  of
packets sent
     and  received,  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 unwise
     to use ping6 during  normal  operations  or  from  automated


     ping6  will report duplicate and damaged packets.  Duplicate
     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 presence
 of low levels of duplicates may not always be cause for
alarm.  Duplicates
 are expected when pinging a broadcast or  multicast
     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).


     The (inter)network layer should never treat packets  differently depending
     on  the  data contained in the data portion.  Unfortunately,
     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
     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  network 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.

RETURN VALUES    [Toc]    [Back]

     ping6 returns 0 on success (the host is alive), and non-zero
if the arguments
 are incorrect or the host is not responding.

EXAMPLES    [Toc]    [Back]

     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
     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,

           $ ping6 -a agl dst.foo.com

SEE ALSO    [Toc]    [Back]

     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, RFC
2463, December

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

HISTORY    [Toc]    [Back]

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

BUGS    [Toc]    [Back]

     ping6 is intentionally separate from ping(8).

OpenBSD      3.6                           May      17,      1998
[ Back ]
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