Usage: iperf [-s|-c host] [options]

iperf [-h|--help] [-v|--version]

Server or Client:

-p, --port # server port to listen on/connect to

-f, --format [kmgKMG] format to report: Kbits, Mbits, KBytes, MBytes

-i, --interval # seconds between periodic bandwidth reports

-F, --file name xmit/recv the specified file

-B, --bind bind to a specific interface

-V, --verbose more detailed output

-J, --json output in JSON format

--logfile f send output to a log file

-d, --debug emit debugging output

-v, --version show version information and quit

-h, --help show this message and quit

Server specific:

-s, --server run in server mode

-D, --daemon run the server as a daemon

-I, --pidfile file write PID file

-1, --one-off handle one client connection then exit

Client specific:

-c, --client run in client mode, connecting to

-u, --udp use UDP rather than TCP

-b, --bandwidth #[KMG][/#] target bandwidth in bits/sec (0 for unlimited)

(default 1 Mbit/sec for UDP, unlimited for TCP)

(optional slash and packet count for burst mode)

-t, --time # time in seconds to transmit for (default 10 secs)

-n, --bytes #[KMG] number of bytes to transmit (instead of -t)

-k, --blockcount #[KMG] number of blocks (packets) to transmit (instead of -t or -n)

-l, --len #[KMG] length of buffer to read or write

(default 128 KB for TCP, 8 KB for UDP)

--cport bind to a specific client port (TCP and UDP, default: ephemeral port)

-P, --parallel # number of parallel client streams to run

-R, --reverse run in reverse mode (server sends, client receives)

-w, --window #[KMG] set window size / socket buffer size

-M, --set-mss # set TCP/SCTP maximum segment size (MTU - 40 bytes)

-N, --no-delay set TCP/SCTP no delay, disabling Nagle's Algorithm

-4, --version4 only use IPv4

-6, --version6 only use IPv6

-S, --tos N set the IP 'type of service'

-Z, --zerocopy use a 'zero copy' method of sending data

-O, --omit N omit the first n seconds

-T, --title str prefix every output line with this string

--get-server-output get results from server

--udp-counters-64bit use 64-bit counters in UDP test packets

[KMG] indicates options that support a K/M/G suffix for kilo-, mega-, or giga-