PING6(8) OpenBSD System Manager's Manual PING6(8)NAMEping6 - send ICMPv6 ECHO_REQUEST packets to network hosts
SYNOPSISping6 [-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
DESCRIPTIONping6 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
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.
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.
If count is 0, send an unlimited number of 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
received. 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
network 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.
-m By default, ping6 asks the kernel to fragment packets to fit into
the minimum IPv6 MTU. -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.
-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
destination. Since the node information multicast group is a
link-local 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
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. 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-
request. -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,
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 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 PACKETSping6 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 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
attached 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 ALSOnetstat(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.
BUGSping6 is intentionally separate from ping(8).
OpenBSD 4.9 June 26, 2010 OpenBSD 4.9
