NAME
ping6 —
send ICMPv6 ECHO_REQUEST
packets to network hosts
SYNOPSIS
ping6 |
[-dfHmnNoqRtvwW]
[-a
addrtype]
[-b
bufsiz]
[-c count]
[-g
gateway]
[-h
hoplimit]
[-I
interface]
[-i wait]
[-l
preload]
[-p
pattern]
[-P
policy]
[-S
sourceaddr]
[-s
packetsize]
[-x
maxwait]
[-X
deadline]
[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 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.
-
-
- -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 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
- 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.
-
-
- -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
- Make the kernel believe that the target
host (or the first hop if you
specify hops) is reachable, by injecting upper-layer
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 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.
-
-
- -x
maxwait
- Time in milliseconds to wait for a reply for each packet
sent.
-
-
- -X
deadline
- Specify a timeout, in seconds, before ping exits regardless
of how many packets have been received.
-
-
- 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, 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.
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 presence of
low levels of duplicates may not always be cause for alarm. Duplicates are
expected when pinging a 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 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.
EXIT STATUS
ping6 exits with 0 on success (the host is alive), and
non-zero if the arguments are incorrect or the host is not responding.
EXAMPLES
Normally,
ping6 works just like
ping(8) would work; the following
will send ICMPv6 echo request to
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.
The following will probe addresses assigned to the destination node,
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,
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 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).