PING(8) UNIX Programmer's Manual PING(8) NAME ping - send ICMP ECHO_REQUEST packets to network hosts SYNOPSIS /etc/ping [ -r ] [ -v ] _h_o_s_t [ _p_a_c_k_e_t_s_i_z_e ] [ _c_o_u_n_t ] 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. _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 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. Other options are: -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 _r_o_u_t_e_d(8C)). -v 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. AUTHOR Mike Muuss Printed 12/27/86 May 23, 1986 1 PING(8) UNIX Programmer's Manual PING(8) SEE ALSO netstat(1), ifconfig(8C) Printed 12/27/86 May 23, 1986 2