SYNOPSIS
fping [ options ] [ systems... ]
DESCRIPTION
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.
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-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‐
rupted).
-C Similar to -c, but the per-target statistics are displayed in a
format designed for automated response-time statistics gathering.
For example:
-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 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.
-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.
#!/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 com‐
mand 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
fping(8)
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