Wednesday, October 13, 2010

Measuring Network Speeds with Netcat and Dd

I've seen a few posts on the web about testing your network speeds with netcat, but they all seem to not work with recent versions of netcat.

On one machine, run:

nc -v -l 2222 > /dev/null

(Make sure you're not blocking connections to 2222!)

On a second machine, run:

dd if=/dev/zero bs=1024K count=512 | nc -v $IP_OF_FIRST_MACHINE 2222

dd will give you your speed:

536870912 bytes (537 MB) copied, 4.87526 s, 117 MB/s

Yay, gigabit!

ymmv, test with /dev/zero at your own risk. Speak with your NOC before starting any network infrastructure changes.


  1. Have you considered using iperf?

  2. iperf seems to work just fine (I hadn't known about it before Martin's reply).

  3. ttcp is also really good for testing line speeds between two machines.

  4. [...] used jbowes method of performance testing. I ran nc on the [...]

  5. Actually used this to test wifi speeds around my house between laptop and a wired server!! Very helpful, thank you. :)


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