PING6(8) System Manager's Manual PING6(8)
ping6 – send ICMPv6 ECHO_REQUEST packets to network hosts
ping6 [-CDdfHmnNoqtvwW] [-a addrtype] [-b bufsiz] [-B boundif] [-c count]
[-G sweepmaxsize[,sweepminsize[,sweepincrsize]]] [-g gateway]
[-G sweep] [-h hoplimit] [-I interface] [-i wait] [-k trafficclass]
[-K netservicetype] [-l preload] [-P policy] [-p pattern]
[-S sourceaddr] [-s packetsize] [-z tclass] [--apple-connect]
[--apple-time] [hops ...] host
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:
Generate ICMPv6 Node Information Node Addresses query, rather than
echo-request. addrtype must be a string constructed of the
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
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.
Set socket buffer size.
Bind the socket to interface This option is an Apple addition.
boundif for sending.
-C Prohibit the socket from using the cellular network interface.
Stop after sending (and receiving) count ECHO_RESPONSE packets. If
this option is specified in conjunction with ping sweeps, each
sweep will consist of count 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, 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 network and should
be used with caution.
sweepmaxsize specifies the maximum size of the payload when sending
sweeping pings and is required for sweeps. sweepminsize specifies
the size of the payload to start with when sending sweeping pings
-- the default value is 0. sweepincrsize specifies the number of
bytes to increment the size of the payload after each sweep when
sending sweeping pings -- the default value is 1. This option is
an Apple addition.
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 unless the option is specified.
Set the IPv6 hoplimit.
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.
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.
Specifies the traffic class to use for sending ICMPv6 packets. The
supported traffic classes are BK_SYS, BK, BE, RD, OAM, AV, RV, VI,
VO and CTL. By default ping6 uses the control traffic class (CTL).
This option is an Apple addition.
Specifies the network service type to use for sending ICMPv6
packets. The supported network service type are BK_SYS, BK, BE,
RV, AV, RD, OAM, VI, SIG and VO. Note this overrides the default
traffic class (-k can still be specified after -K to use both).
This option is an Apple addition.
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
-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 computed 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.
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.
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.
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.
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.
Use the specified traffic class.
Connects the socket to the destination address. This option is an
Prints the time a packet was received. This option is an Apple
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
displayed, 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. 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 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
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 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.
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.
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
ping6 -w ff02::1%wi0
The following will probe addresses assigned to the destination node,
ping6 -a agl dst.foo.com
netstat(1), icmp6(4), inet6(4), ip6(4), ifconfig(8), ping(8), routed(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.
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.
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
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 uniform 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 protocol such as IPv6. Thus, even if we had a unified ping(8)
command for both IPv4 and IPv6, we would usually 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.
macOS 12.1 March 29, 2013 macOS 12.1