fping - send ICMP ECHO_REQUEST packets to network hosts
fping [ options ] [ systems... ]
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).
- -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).
- -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.
- -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. This option can only be used by the root
user. Regular users should pipe in the file via stdin:
$ fping < targets_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).
- -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:
<http://my-netdata.io/>
- -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.
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
- 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
- David Schweikert, versions 3.0 and up
fping website: <http://www.fping.org>
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.
If fping was configured with
"--enable-safe-limits", the following
values are not allowed for non-root users:
- -i n, where n < 1 msec
- -p n, where n < 10 msec