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.

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).

       -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 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 (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

       -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, --quet
            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 show summary results every n 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, --src
            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.

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

       •   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>

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.

RESTRICTIONS

       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

SEE ALSO

       ping(8)