Provided by: fping_2.4b2-to-ipv6-16.1_amd64 bug

NAME

       fping - send ICMP ECHO_REQUEST packets to network hosts

SYNOPSIS

       fping [ options ] [ systems... ]

DESCRIPTION

       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.

OPTIONS

       -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 interrupted).

       -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 192.168.1.0/24

            or

            fping -g 192.168.1.0 192.168.1.255

       -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.

       -Saddr
            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.

EXAMPLES

       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.

       #!/usr/bin/perl
       require 'open2.pl';

       $MAILTO = "root";

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

       @check=("slapshot","foo","foobar");

       foreach(@check) {  print INPUT "$_\n"; }
       close(INPUT);
       @output=<OUTPUT>;

       if ($#output != -1) {
        chop($date=`date`);
        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.

       #!/usr/bin/perl

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

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

AUTHORS

       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

DIAGNOSTICS

       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.

BUGS

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

RESTRICTIONS

       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
       following:

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

SEE ALSO

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

                                                                                         fping(8)