ping(1M) TCP/IP 5.4R2.01p03 ping(1M)
NAME
ping - send ICMP ECHO_REQUEST packets to network hosts
SYNOPSIS
ping host [ timeout ]
ping -s [ -dfnqrRv ] [ -c count ] [ -i wait ] [ -l preload ] [ -p
pattern ] host [ packetsize ]
DESCRIPTION
The DARPA Internet is a large and complex aggregation of network
hardware, connected together by gateways. Tracking a single-point
hardware or software failure can often be difficult. Ping utilizes
the ICMP protocol's mandatory ECHO_REQUEST datagram to elicit an ICMP
ECHO_RESPONSE from a host or gateway. ECHO_REQUEST datagrams
(``pings'') have an IP and ICMP header, followed by a struct timeval,
and then an arbitrary number of ``pad'' bytes used to fill out the
packet. Default datagram length is 64 bytes, but this may be changed
using the command-line option.
The default mode of ping sends out ECHO_REQUEST datagrams once a
second until either a response is received (``host is alive'') or the
timeout expires (``no answer from host''). The -s statistics option
is used to set BSD ping semantics which continuously polls and prints
roundtrip delay information. Other options are:
-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.
-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, ping sends that many packets
as fast as possible before falling into its normal mode of
behavior.
-n Numeric output only. No attempt will be made to look up
symbolic names for host addresses.
-p pattern You may specify up to 16 "pad" bytes to fill out the
packet you send. The "pad" bytes must be specified in
hexidecimal format. For example, "-p ff" will cause the sent
packet to be filled with all ones. This is useful for
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ping(1M) TCP/IP 5.4R2.01p03 ping(1M)
diagnosing data-dependent problems in a network.
-q Quiet output. Nothing is displayed except the summary lines
at startup time and when finished.
-r Bypass the normal routing tables and send directly to a host
on an attached network. If the host is not on a directly
attached network, an error is returned. This option can be
used to ping a local host through an interface that has no
route through it (e.g., after the interface was dropped by
routed(1M)).
-R Insert "record route" IP option in outgoing packets,
summarizing routes taken when program exits.
-v Verbose output. ICMP packets other than ECHO RESPONSE that
are received are listed.
When using ping 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 farther and farther away should be
``pinged''. Ping sends one datagram per second, and prints one line
of output for every ECHO_RESPONSE returned. No output is produced if
there is no response. If an optional count is given, only that
number of requests is sent. Round-trip times and packet loss
statistics are computed. When all responses have been received or
the program times out (with count specified), or if the program is
terminated with a SIGINT, a brief summary is displayed.
This program is intended for use in network testing, measurement, and
management. It should be used primarily for manual fault isolation.
SEE ALSO
ifconfig(1M), netstat(1M), traceroute(1M).
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