_O_n_l_i_n_e _M_a_n_u_a_l        System Manager Commands              ping(8)



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     ping - send ICMP ECHO_REQUEST packets to network hosts

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     ////eeeettttcccc////ppppiiiinnnngggg [ ----rrrr ] [ ----vvvv ] _h_o_s_t [ _p_a_c_k_e_t_s_i_z_e ] [ _c_o_u_n_t ]

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     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.  _P_i_n_g 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 ssssttttrrrruuuucccctttt ttttiiiimmmmeeeevvvvaaaallll, 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.  Other options
     are:

     ----rrrr   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 _r_o_u_t_e_d(8c)).

     ----vvvv   Verbose output.  ICMP packets other than ECHO_RESPONSE
          that are received are listed.

     When using _p_i_n_g for fault isolation, it should first be run
     on the local host, to verify that the local network inter-
     face is up and running.  Then, hosts and gateways further
     and further away should be ``pinged''.  _P_i_n_g 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 _c_o_u_n_t 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 a _c_o_u_n_t specified),
     or if the program is terminated with a SIGINT, a brief sum-
     mary is displayed.

     This program is intended for use in network testing, meas-
     urement and management.  It should be used primarily for
     manual fault isolation.  Because of the load it could impose
     on the network, it is unwise to use _p_i_n_g during normal
     operations or from automated scripts.

AAAAUUUUTTTTHHHHOOOORRRR
     Mike Muuss

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     User Commands (1): netstat
     System Manager Commands (8): ifconfig

December 1989                      TX System Manager's Reference