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       fping - send ICMP ECHO_REQUEST packets to network hosts


       fping [ options ] [ systems... ]


       fping is a program like ping(8) which uses the Internet Control Message
       Protocol  (ICMP)  echo  request  to  determine  if  a  target  host  is
       responding.  fping differs from ping in that you can specify any number
       of targets on the command line, or specify a file containing the  lists
       of targets to ping. Instead of sending to one target until it times out
       or replies, fping will send out a ping packet and move on to  the  next
       target in a round-robin fashion.

       In  the default mode, if a target replies, it is noted and removed from
       the list of targets to check; if a target does  not  respond  within  a
       certain  time limit and/or retry limit it is designated as unreachable.
       fping also supports sending a specified number of pings to a target, or
       looping indefinitely (as in ping ).

       Unlike  ping,  fping  is  meant to be used in scripts, so its output is
       designed to be easy to parse.


       -a   Show systems that are alive.

       -A   Display targets by address rather than DNS name.

       -bn  Number of bytes of ping data to send.  The minimum size  (normally
            12)  allows  room  for  the  data  that fping needs to do its work
            (sequence number, timestamp).  The  reported  received  data  size
            includes  the  IP  header  (normally  20 bytes) and ICMP header (8
            bytes), so the minimum total size is 40 bytes.  Default is 56,  as
            in  ping.   Maximum  is  the  theoretical maximum IP datagram size
            (64K), though most  systems  limit  this  to  a  smaller,  system-
            dependent number.

       -Bn  In  the  default  mode,  fping  sends several requests to a target
            before giving up, waiting longer for a reply  on  each  successive
            request.   This  parameter  is the value by which the wait time is
            multiplied on each successive request; it must  be  entered  as  a
            floating-point number (x.y).  The default is 1.5.

       -c   Number of request packets to send to each target.  In this mode, a
            line is displayed for each received response (this can  suppressed
            with  -q or -Q).  Also, statistics about responses for each target
            are  displayed  when  all  requests  have  been  sent   (or   when

       -C   Similar  to  -c,  but the per-target statistics are displayed in a
            format designed for automated response-time statistics  gathering.
            For example:

            % fping -C 5 -q somehost

            somehost : 91.7 37.0 29.2 - 36.8

            shows  the  response  time  in  milliseconds  for each of the five
            requests, with the "-" indicating that no response was received to
            the fourth request.

       -d   Use  DNS  to lookup address of return ping packet. This allows you
            to give fping a list of IP addresses as input and print  hostnames
            in the output.

       -e   Show elapsed (round-trip) time of packets.

       -f   Read list of targets from a file.  This option can only be used by
            the root user.  Regular users should pipe in the file via stdin:

            % fping < targets_file

       -g   Generate a target list from a supplied IP netmask, or  a  starting
            and  ending  IP.   Specify the netmask or start/end in the targets
            portion of the command line.

            ex. To ping the class C 192.168.1.x, the  specified  command  line
            could look like either:

            fping -g


            fping -g

       -h   Print usage message.

       -in  The  minimum  amount  of  time (in milliseconds) between sending a
            ping packet to any target (default is 25).

       -l   Loop  sending  packets  to  each  target  indefinitely.   Can   be
            interrupted with ctl-C; statistics about responses for each target
            are then displayed.

       -m   Send pings to each of a target host’s multiple interfaces.

       -n   Same as -d.

       -p   In looping or counting modes (-l, -c, or -C), this parameter  sets
            the  time  in  milliseconds  that  fping  waits between successive
            packets to an individual target.  Default is 1000.

       -q   Quiet. Don’t show per-target results, just set final exit  status.

       -Qn  Like -q, but show summary results every n seconds.

       -rn  Retry limit (default 3). This is the number of times an attempt at
            pinging a target will be made, not including the first try.

       -s   Print cumulative statistics upon exit.

            Set source address.

       -tn  Initial target timeout  in  milliseconds  (default  500).  In  the
            default  mode,  this  is the amount of time that fping waits for a
            response to its first request.  Successive timeouts are multiplied
            by the backoff factor.

       -Tn  Select timeout in seconds (default 10).

       -u   Show targets that are unreachable.

       -v   Print fping version information.


       The  following  perl script will check a list of hosts and send mail if
       any are unreachable. It uses the open2 function which allows a  program
       to  be opened for reading and writing. fping does not start pinging the
       list of systems until it reads  EOF,  which  it  gets  after  INPUT  is
       closed.  Sure the open2 usage is not needed in this example, but it’s a
       good open2 example none the less.

       require ’’;

       $MAILTO = "root";

       $pid = &open2("OUTPUT","INPUT","/usr/local/bin/fping -u");


       foreach(@check) {  print INPUT "$_\n"; }

       if ($#output != -1) {
        open(MAIL,"|mail -s ’unreachable systems’ $MAILTO");
        print MAIL "\nThe following systems are unreachable as of: $date\n\n";
        print MAIL @output;
        close MAIL;

       Another good example is when you want to perform an action only on hosts
       that are currently reachable.


       $hosts_to_backup = ‘cat /etc/hosts.backup | fping -a‘;

       foreach $host (split(/\n/,$hosts_to_backup)) {
         # do it


       Roland J. Schemers III, Stanford University, concept and versions 1.x
       RL "Bob" Morgan, Stanford University, versions 2.x
       David Papp, versions 2.3x and up,
       fping website:


       Exit status is 0 if all the hosts are reachable, 1 if some  hosts  were
       unreachable,  2  if  any  IP  addresses  were  not found, 3 for invalid
       command line arguments, and 4 for a system call failure.


       Ha! If we knew of any we would have fixed them!


       If certain options are used (i.e, a low value for -i and -t, and a high
       value for -r) it is possible to flood the network. This program must be
       installed as setuid root in order to open up a raw socket, or  must  be
       run  by  root.  In  order  to stop mere mortals from hosing the network
       (when fping is installed setuid root) , normal users can’t specify  the

        -i n   where n < 10  msec
        -r n   where n > 20
        -t n   where n < 250 msec


       netstat(1), ping(8), ifconfig(8c)