iperf: unrecognized option `--VERSION' Usage: iperf [-s|-c host] [options] Try `iperf --help' for more information.

Usage: iperf [-s|-c host] [options] iperf [-h|--help] [-v|--version] Client/Server: -b, --bandwidth #[kmgKMG | pps] bandwidth to send at in bits/sec or packets per second -e, --enhancedreports use enhanced reporting giving more tcp/udp and traffic information -f, --format [kmgKMG] format to report: Kbits, Mbits, KBytes, MBytes -i, --interval # seconds between periodic bandwidth reports -l, --len #[kmKM] length of buffer in bytes to read or write (Defaults: TCP=128K, v4 UDP=1470, v6 UDP=1450) -m, --print_mss print TCP maximum segment size (MTU - TCP/IP header) -o, --output <filename> output the report or error message to this specified file -p, --port # server port to listen on/connect to -u, --udp use UDP rather than TCP --udp-counters-64bit use 64 bit sequence numbers with UDP -w, --window #[KM] TCP window size (socket buffer size) -z, --realtime request realtime scheduler -B, --bind <host> bind to <host>, an interface or multicast address -C, --compatibility for use with older versions does not sent extra msgs -M, --mss # set TCP maximum segment size (MTU - 40 bytes) -N, --nodelay set TCP no delay, disabling Nagle's Algorithm -S, --tos # set the socket's IP_TOS (byte) field Server specific: -s, --server run in server mode -t, --time # time in seconds to listen for new connections as well as to receive traffic (default not set) -U, --single_udp run in single threaded UDP mode -D, --daemon run the server as a daemon -V, --ipv6_domain Enable IPv6 reception by setting the domain and socket to AF_INET6 (Can receive on both IPv4 and IPv6) Client specific: -c, --client <host> run in client mode, connecting to <host> -d, --dualtest Do a bidirectional test simultaneously -n, --num #[kmgKMG] number of bytes to transmit (instead of -t) -r, --tradeoff Do a bidirectional test individually -t, --time # time in seconds to transmit for (default 10 secs) -B, --bind [<ip> | <ip:port>] bind src addr(s) from which to originate traffic -F, --fileinput <name> input the data to be transmitted from a file -I, --stdin input the data to be transmitted from stdin -L, --listenport # port to receive bidirectional tests back on -P, --parallel # number of parallel client threads to run -R, --reverse reverse the test (client receives, server sends) -T, --ttl # time-to-live, for multicast (default 1) -V, --ipv6_domain Set the domain to IPv6 (send packets over IPv6) -X, --peer-detect perform server version detection and version exchange -Z, --linux-congestion <algo> set TCP congestion control algorithm (Linux only) Miscellaneous: -x, --reportexclude [CDMSV] exclude C(connection) D(data) M(multicast) S(settings) V(server) reports -y, --reportstyle C report as a Comma-Separated Values -h, --help print this message and quit -v, --version print version information and quit [kmgKMG] Indicates options that support a k,m,g,K,M or G suffix Lowercase format characters are 10^3 based and uppercase are 2^n based (e.g. 1k = 1000, 1K = 1024, 1m = 1,000,000 and 1M = 1,048,576) The TCP window size option can be set by the environment variable TCP_WINDOW_SIZE. Most other options can be set by an environment variable IPERF_<long option name>, such as IPERF_BANDWIDTH. Source at <http://sourceforge.net/projects/iperf2/> Report bugs to <iperf-users@lists.sourceforge.net>