We have a Netgear FVS336G VPN firewall at our office and we use it to access our e-mail and files when we are working from home/outside of the office.

At present, the performance is not too bad, however, sometimes it can take quite a while to complete a small file transfer.

What I want to do is test the performance of the VPN connection (i.e. baseline it) and try a few things on a test VPN policy that I have created.

For example, I want to measure the speed on different algorithms - right now, the main policy everyone is using is set to 3DES; from what I have read, AES is 'faster' (as well as being more CPU friendly and secure), however, when I tried it on my test policy, I did not notice very much - of course, this doesn't mean anything as it's not very scientific... I'm just looking at a bunch of numbers on the screen and trying to determine which is higher.

What I am looking for is some sort of command prompt/line based tool that will bypass all the Windows (the environment is all Windows based) file transfer-y stuff. For example, the 'discovering' phase which takes about a minute or two to complete before it gets on to actually transferring the file.

Is there such a tool for a Windows platform that will help me measure the performance accurately?


I did quite a bit of bandwidth testing recently with OpenVPN tunnels and I found that iperf gave me the best results. I wanted something that would purely rely on the network speed and not the hard drive speed. Also make you sure set the packet size higher than the defaults if you are going for quite a bit of bandwidth.


iperf -l 64k -w 64k -p 5001 -s


iperf -l 64k -w 64k -p 5001 -c X.X.X.X

It's also a good idea to set these windows the same on both ends because Linux default window size is different than Windows, which caused me a lot of issues with inconsistent results.

  • Thanks for the example syntax usage above. I tweaked it to run for slightly longer using the -t flag :) May need to play with the window sizes too - thanks! – emtunc Dec 17 '10 at 19:54

Just to name a few: nuttcp,iperf,netperf.

If you want to baseline/monitor on a regular basis I'd deploy on of the Internet2's PerfSonar[1] VM images behind the concentrator - I found the Web100 Linux kernel very valuable when it comes to performance of internet links and if you need to debug that.


  • Thanks for answering with the different alternatives available :-) I am trying out iperf right now but will most likely play around with the others at some point - thanks again. – emtunc Dec 17 '10 at 19:56

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