send ICMPv6 ECHO_REQUEST packets to
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, followed by an ICMPv6 header formatted as documented in
RFC 4443. The options are as follows:
- Generate an ICMPv6 Node Information Node Addresses query, rather than an
echo-request. addrtype must be a string constructed
of the following characters:
- 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.
- 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.
- Requests responder's IPv4-compatible and IPv4-mapped addresses.
- Requests responder's global-scope addresses.
- Requests responder's link-local addresses.
- Requests responder's site-local addresses.
- Set the socket buffer size.
- Stop after sending (and receiving) count
ECHO_RESPONSEpackets. If count is 0, send an unlimited number of packets.
- Set the
SO_DEBUGoption on the socket being used.
- 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.
- 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.
- Flood ping. Outputs packets as fast as they come back or one hundred times
per second, whichever is more. For every
ECHO_REQUESTsent a period (‘.’) is printed, while for every
ECHO_REPLYreceived 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.
- Specifies to use gateway as the next hop to the destination. The gateway must be a neighbor of the sending node.
- Specifies to try reverse-lookup of IPv6 addresses. The
ping6command 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
sending each packet. The default is to wait for one second between
each packet. This option is incompatible with the
- If preload is specified,
ping6sends that many packets as fast as possible before falling into its normal mode of behavior. Only the super-user may use this option.
- By default,
ping6asks the kernel to fragment packets to fit into the minimum IPv6 MTU.
-mwill 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.
- 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
- Numeric output only. No attempt will be made to look up symbolic names from addresses in the reply.
- 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.
- Quiet output. Nothing is displayed except the summary lines at startup time and when finished.
- 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. It may also be necessary to specify
-bto extend the socket buffer size.
This option is ignored if any of the flags [
-tWw] are specified.
- Generate an ICMPv6 Node Information query, rather than echo-request.
-shas no effect if this option is specified.
- Set the routing table to be used for outgoing packets.
- Verbose output. All ICMP packets that are received are listed.
- The same as
-w, but with the old packet format based on the 03 draft. This option is present for backward compatibility.
-shas no effect if this option is specified.
- Generate an ICMPv6 Node Information DNS Name query, rather than
-shas no effect if this option is specified.
- IPv6 addresses of intermediate nodes, which will be put into a type 0 routing header.
- The IPv6 address of the final destination node.
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
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 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
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
ping6 exits 0 if at least one reply is
received, and >0 if no reply is received or an error occurred.
ping6 works just like
ping(8) would work; the following will send ICMPv6 echo request to
$ 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
netstat(1), icmp6(4), inet6(4), ip6(4), ifconfig(8), ping(8), route6d(8), traceroute6(8)
A. Conta, S. Deering, and M. Gupta, Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification, RFC 4443, March 2006.
M. Crawford and B. Haberman, IPv6 Node Information Queries, RFC 4620, August 2006.
The ping(8) command first appeared in
with IPv6 support first appeared in the WIDE Hydrangea IPv6 protocol stack
ping6 is intentionally separate from