FPING(8) FPING(8)

NAME

fping - send ICMP ECHO_REQUEST packets to network hosts

SYNOPSIS

fping [ options ] [ systems... ]

DESCRIPTION

fping is a program like ping 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. Current
statistics can be obtained without termination of process with signal
SIGQUIT (^\ from the keyboard on most systems).

OPTIONS

-4, --ipv4
Restrict name resolution and IPs to IPv4 addresses.

-6, --ipv6
Restrict name resolution and IPs to IPv6 addresses.

-a, --alive
Show systems that are alive.

-A, --addr
Display targets by address rather than DNS name. Combined with
-d, the output will be both the ip and (if available) the
hostname.

-b, --size=BYTES
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.

-B, --backoff=N
Backoff factor. 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 (-t) is multiplied on each successive
request; it must be entered as a floating-point number (x.y).
The default is 1.5.

-c, --count=N
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). This option overrides -a or -u.

-C, --vcount=N
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. This option overrides -a or -u.

-d, --rdns
Use DNS to lookup address of ping target. This allows you to
give fping a list of IP addresses as input and print hostnames
in the output. This is similar to option -n/--name, but will
force a reverse-DNS lookup even if you give hostnames as target
(NAME->IP->NAME).

-D, --timestamp
Add Unix timestamps in front of output lines generated with in
looping or counting modes (-l, -c, or -C).

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

-f, --file
Read list of targets from a file.

-g, --generate addr/mask
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. If a network with netmask is given,
the network and broadcast addresses will be excluded. ex. To
ping the network 192.168.1.0/24, the specified command line
could look like either:

$ fping -g 192.168.1.0/24

or

$ fping -g 192.168.1.1 192.168.1.254

-h, --help
Print usage message.

-H, --ttl=N
Set the IP TTL field (time to live hops).

-i, --interval=MSEC
The minimum amount of time (in milliseconds) between sending a
ping packet to any target (default is 10, minimum is 1).

-I, --iface=IFACE
Set the interface (requires SO_BINDTODEVICE support).

-k, --fwmark=FWMARK
Set FWMARK on ping packets for policy-based routing. Requires
Linux kernel 2.6.25<=, and root privileges or cap_net_admin.

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

-m, --all
Send pings to each of a target host's multiple IP addresses (use
of option '-A' is recommended).

-M, --dontfrag
Set the "Don't Fragment" bit in the IP header (used to
determine/test the MTU).

-n, --name
If targets are specified as IP addresses, do a reverse-DNS
lookup on them to print hostnames in the output.

-N, --netdata
Format output for netdata (-l -Q are required). See:
<https://netdata.cloud/>

-o, --outage
Calculate "outage time" based on the number of lost pings and
the interval used (useful for network convergence tests).

-O, --tos=N
Set the typ of service flag (TOS). N can be either decimal or
hexadecimal (0xh) format.

-p, --period=MSEC
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 and
minimum is 10.

-q, --quiet
Quiet. Don't show per-probe results, but only the final summary.
Also don't show ICMP error messages.

-Q, --squiet=SECS
Like -q, but additionally show interval summary results every
SECS seconds.

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

-R, --random
Instead of using all-zeros as the packet data, generate random
bytes. Use to defeat, e.g., link data compression.

-s, --stats
Print cumulative statistics upon exit.

-S, --src=addr
Set source address.

-t, --timeout=MSEC
Initial target timeout in milliseconds. In the default, non-loop
mode, the default timeout is 500ms, and it represents the amount
of time that fping waits for a response to its first request.
Successive timeouts are multiplied by the backoff factor
specified with -B.

In loop/count mode, the default timeout is automatically
adjusted to match the "period" value (but not more than 2000ms).
You can still adjust the timeout value with this option, if you
wish to, but note that setting a value larger than "period"
produces inconsistent results, because the timeout value can be
respected only for the last ping.

Also note that any received replies that are larger than the
timeout value, will be discarded.

-T n Ignored (for compatibility with fping 2.4).

-u, --unreach
Show targets that are unreachable.

-v, --version
Print fping version information.

-x, --reachable=N
Given a list of hosts, this mode checks if number of reachable
hosts is >= N and exits true in that case.

-X, --fast-reachable=N
Given a list of hosts, this mode immediately exits true once N
alive hosts have been found.

EXAMPLES

Generate 20 pings to two hosts in ca. 1 second (i.e. one ping every
50 ms to each host), and report every ping RTT at the end:

$ fping --quiet --interval=1 --vcount=20 --period=50 127.0.0.1 127.0.0.2

AUTHORS

+o Roland J. Schemers III, Stanford University, concept and versions
1.x

+o RL "Bob" Morgan, Stanford University, versions 2.x

+o David Papp, versions 2.3x and up

+o David Schweikert, versions 3.0 and up

fping website: <http://www.fping.org>

DIAGNOSTICS

Exit status is 0 if all the hosts (or the number of hosts specified
with -x or -X) are reachable, 1 if some (or too many with -x or -X)
hosts were unreachable, 2 if any IP addresses were not found, 3 for
invalid command line arguments, and 4 for a system call failure.

RESTRICTIONS

If fping was configured with "--enable-safe-limits", the following
values are not allowed for non-root users:

+o -i n, where n < 1 msec

+o -p n, where n < 10 msec

SEE ALSO

ping(8)

fping 2024-04-21 FPING(8)