Perform network throughput tests


iperf2 -s [ options ]

iperf2 -c server [ options ]

iperf2 -u -s [ options ]

iperf2 -u -c server [ options ]

Runs on:

QNX Neutrino


The general options include:

-B host
--bind host
Bind to host, an interface or multicast address.
For use with older versions; don't send extra msgs.
-f k|m|K|M
--format k|m|K|M
The format to report: Kbits, Mbits, KBytes, MBytes.
Print a help synopsis.
-i n
--interval n
Pause for n seconds between periodic bandwidth reports.
-l n[K|M]
--len n[K|M]
Set the length of the read/write buffer to n (default 8 KB).
-M n
--mss n
Set the TCP maximum segment size (MTU - 40 bytes).
Print the TCP maximum segment size (MTU - TCP/IP header).
Set TCP no delay, disabling Nagle's Algorithm.
-o filename
--output filename
Output the report or error message to the specified file.
-p n
--port n
Set the server port to listen on/connect to to n (default 5001).
Use UDP rather than TCP.
Print version information, and then exit.
Set the domain to IPv6.
-w n[K|M]
--window n[K|M]
Set the TCP window size (socket buffer size).
-x C|D|M|S|V
--reportexclude C|D|M|S|V
Exclude C(connection), D(data), M(multicast), S(settings), or V(server) reports.
-y C|c
--reportstyle C|c
If set to C or c, report results as CSV (comma-separated values).

The server-specific options include:

Run the server as a daemon.
Run in server mode.
Run in single-threaded UDP mode.

The client-specific options include:

-b n[K|M]
--bandwidth n[K|M]
Set the target bandwidth to n bits/sec (default 1 Mbit/sec). This setting requires UDP (-u).
-c host
--client host
Run in client mode, connecting to host.
Do a bidirectional test simultaneously.
-F name
--fileinput name
Input the data to be transmitted from a file.
Input the data to be transmitted from stdin.
-L n
--listenport n
The port to recieve bidirectional tests back on.
-n n[K|M]
--num n[K|M]
The number of bytes to transmit (instead of -t).
-P n
--parallel n
The number of parallel client threads to run.
Do a bidirectional test individually.
-T n
--ttl n
The time-to-live, for multicast (default 1).
-t n
--time n
The time in seconds to transmit for (default 10 secs).


The iperf2 tool measures network throughput. It can test either TCP or UDP throughput. To perform an iperf2 test, you must establish both a server (to discard traffic) and a client (to generate traffic).

For a different version of this tool, see iperf3.

Environment variables:

Controls the size of TCP buffers.

Contributing author:

iperf2 was originally written by Mark Gates and Alex Warshavsky. Man page and maintence by Jon Dugan jdugan at x1024 dot net. Other contributions from Ajay Tirumala, Jim Ferguson, Feng Qin, Kevin Gibbs, John Estabrook jestabro at ncsa.uiuc.edu, Andrew Gallatin gallatin at gmail.com>, and Stephen Hemminger shemminger at linux-foundation.org.

See also http://iperf2.sourceforge.net/.