TCPSpray for Windows

There is a well known network utility for Unix called tcpspray which is used to measure network speed between two computers. To my knowledge there has not been an equivalent program for people running Windows, so I wrote one.



In a DOS Prompt window write, with the program in your path:
tcpspray hostname
or (for help):
tcpspray -h


D:\bin> tcpspray host
Transmitted 102400 bytes in 0.220 seconds (454.545±21.645 kbytes/s)

This says that you can transfer ca 455KB per second to the target host, with a margin of plus/minus 20. This margin is because of the granularity in the time measurement. If you think it's too high, you should send a larger amount of data.


It just says 'Connection refused' The tcpspray program uses a TCP service called 'discard' on the target computer, but that service isn't always present. It exists on most unix machines, but even there, many has turned it off to keep the machine as secure as possible. It's also part of the "Simple TCP/IP Services" in Windows NT. I don't know about Macintosh or other OS:es.
There is a strange character in the speed report. It is a '±'-character in the Latin-1 character set. DOS-boxes in Win95 as well as WinNT uses an old character table which is somewhat incompatible with Latin-1 (ISO 8859-1). I have still not decided how to do with that.

Release History

May 2, 1998 version 1.2, the sent data is no longer a simple stream of zeroes but a random byte string. That may make some strange results more difficult to reproduce but on the other hand, the modem compression no longer affects the result in any significant way.
April 7, 1998 version 1.1, now you can interrupt the program and still get the result measured so far.
Winter 1997 version 1.01 and 1.01a, some minor fixes.
October 6, 1997 version 1.0, first release.

Daniel Bratell,