Switch to SpeakEasy.net DSL

The Modular Manual Browser

Home Page
Manual: (Debian-3.1)
Apropos / Subsearch:
optional field

fping(8)                    System Manager's Manual                   fping(8)

       fping - send ICMP ECHO_REQUEST packets to network hosts

       fping [ options ] [ systems... ]

       fping  is a like program which uses the Internet Control Message Proto-
       col (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 tar-
       get 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-depen-
            dent 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  inter-

       -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  inter-
            rupted  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 pack-
            ets 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.

       -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.

       -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 'open2.pl';

       $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:  http://www.fping.com

       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  com-
       mand 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)