send ICMP ECHO_REQUEST packets to network hosts
List alive hosts within a subnet generated from a netmask
List alive hosts within a subnet generated from an IP range
List unreachable hosts within a subnet generated from a netmask
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.
Restrict name resolution and IPs to IPv4 addresses.
Restrict name resolution and IPs to IPv6 addresses.
Show systems that are alive.
Display targets by address rather than DNS name. Combined with -d,
the output will be both the ip and (if available) the hostname.
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-
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.
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
Similar to -c, but the per-target statistics are displayed in a
format designed for automated response-time statistics gathering.
$ 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.
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. This is similar to option -n/--name, but will force
a reverse-DNS lookup even if you give hostnames as target
Add Unix timestamps in front of output lines generated with in
looping or counting modes (-l, -c, or -C).
Show elapsed (round-trip) time of packets.
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
$ fping -g 192.168.1.0/24
$ fping -g 192.168.1.1 192.168.1.254
Print usage message.
Set the IP TTL field (time to live hops).
The minimum amount of time (in milliseconds) between sending a
ping packet to any target (default is 10, minimum is 1).
Set the interface (requires SO_BINDTODEVICE support).
Loop sending packets to each target indefinitely. Can be
interrupted with Ctrl-C; statistics about responses for each
target are then displayed.
Send pings to each of a target host's multiple IP addresses (use
of option '-A' is recommended).
Set the "Don't Fragment" bit in the IP header (used to
determine/test the MTU).
If targets are specified as IP addresses, do a reverse-DNS lookup
on them to
Format output for netdata (-l -Q are required). See:
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
• RL "Bob" Morgan, Stanford University, versions 2.x
• David Papp, versions 2.3x and up
• David Schweikert, versions 3.0 and up
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