Manual Pages for UNIX Darwin command on man ping6

PING6(8) BSD System Manager's Manual PING6(8)

NAME

ppiinngg66 - send ICMPv6 ECHOREQUEST packets to network hosts

SYNOPSIS

ppiinngg66 [-ddffHHnnNNqqRRttvvwwWW] [-aa addrtype] [-bb bufsiz] [-cc count] [-hh hoplimit]

[-II interface] [-ii wait] [-ll preload] [-pp pattern] [-PP policy]

[-SS sourceaddr] [-ss packetsize] [hops...] host

DESCRIPTION

ppiinngg66 uses the ICMPv6 protocol's mandatory ICMP6ECHOREQUEST datagram to elicit an ICMP6ECHOREPLY from a host or gateway. ICMP6ECHOREQUEST datagrams (``pings'') have an IPv6 header, and ICMPv6 header formatted as documented in RFC2463. The options are as follows:

-aa addrtype

Generate ICMPv6 Node Information Node Addresses query, rather

than echo-request. addrtype must be a string constructed of the

following characters. aa requests all the responder's unicast addresses. If the character is omitted, only those addresses which belong to the interface which has the responder's address are requests.

cc requests responder's IPv4-compatible and IPv4-mapped

addresses.

gg requests responder's global-scope addresses.

ss requests responder's site-local addresses.

ll requests responder's link-local addresses.

AA 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.

-bb bufsiz

Set socket buffer size.

-cc count

Stop after sending (and receiving) count ECHORESPONSE packets.

-dd Set the SODEBUG option on the socket being used.

-ff Flood ping. Outputs packets as fast as they come back or one

hundred times per second, whichever is more. For every ECHOREQUEST sent a period ``.'' is printed, while for every ECHOREPLY 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.

-HH Specifies to try reverse-lookup of IPv6 addresses. The ppiinngg66

command does not try reverse-lookup unless the option is speci-

fied.

-hh hoplimit

Set the IPv6 hoplimit.

-II 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.

-ii wait

Wait wait seconds between sending each packet. The default is to

wait for one second between each packet. This option is incom-

patible with the -ff option.

-ll preload

If preload is specified, ppiinngg66 sends that many packets as fast as possible before falling into its normal mode of behavior. Only

the super-user may use this option.

-nn Numeric output only. No attempt will be made to lookup symbolic

names from addresses in the reply.

-NN 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, destination link needs to be specified by -II option.

-pp 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.

-PP policy

policy specifies IPsec policy to be used for the probe.

-qq Quiet output. Nothing is displayed except the summary lines at

startup time and when finished.

-RR Make the kernel believe that the target host (or the first hop if

you specify hops) is reachable, by injecting upper-layer reacha-

bility confirmation hint. The option is meaningful only if the target host (or the first hop) is a neighbor.

-SS sourceaddr

Specifies the source address of request packets. The source address must be one of the unicast addresses of the sending node.

If the outgoing interface is specified by the -II option as well,

sourceaddr needs to be an address assigned to the specified interface.

-ss 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 -bb as

well to extend socket buffer size.

-tt Generate ICMPv6 Node Information supported query types query,

rather than echo-request. -ss has no effect if -tt is specified.

-vv Verbose output. ICMP packets other than ECHORESPONSE that are

received are listed.

-ww Generate ICMPv6 Node Information DNS Name query, rather than

echo-request. -ss has no effect if -ww is specified.

-WW Same as -ww, but with old packet format based on 03 draft. This

option is present for backward compatibility. -ss has no effect

if -ww is specified.

hops IPv6 addresses for intermediate nodes, which will be put into type 0 routing header. host IPv6 adddress of the final destination node. When using ppiinngg66 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 calcula-

tion, although the round trip time of these packets is used in calculat-

ing 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 man-

agement. Because of the load it can impose on the network, it is unwise to use ppiinngg66 during normal operations or from automated scripts. DDUUPPLLIICCAATTEE AANNDD DDAAMMAAGGEEDD PPAACCKKEETTSS ppiinngg66 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 pres-

ence 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 ppiinngg66 packet's path (in the network or in the hosts). TTRRYYIINNGG DDIIFFFFEERREENNTT DDAATTAA PPAATTTTEERRNNSS 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

-pp option of ppiinngg66.

RETURN VALUES

ppiinngg66 returns 0 on success (the host is alive), and non-zero if the argu-

ments are incorrect or the host is not responding. EEXXAAMMPPLLEESS

Normally, ping6(8) 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

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

BUGS

There have been many discussions on why we separate ping6(8) 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 request. 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 reacha-

bility 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 -66 or -44

option (or something like those) to specify the particular address fam-

ily. This essentially means that we have two different commands. HISTORY

The ping(8) command appeared in 4.3BSD. The ppiinngg66 command with IPv6 sup-

port first appeared in 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 BSD May 17, 1998 BSD