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We need to simulate an unstable network connection to try to debug some connectivity issues in our server/client application and I was wondering if there are any programs out there that can simulate those conditions such as on a faint wireless network.

I'm not just referring to reducing bandwidth, but also reducing reliability, frequent on and off, short bursts of disconnectedness, etc.

JYelton
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Davy8
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  • possible duplicate of [Network simulator?](http://stackoverflow.com/questions/262282/network-simulator) – AShelly Mar 07 '14 at 19:14

3 Answers3

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I used a tool called netem that runs on linux. It allows you to increase packet loss at a given percentage, introduce delays within packets and handle packet re-ordering. Basically it's designed to emulate different networks.

All you need to get it up and running is a spare machine to install Linux on with a couple of Ethernet cards. Hook it up as a bridge, and run netem between them. Should be quite simple to do. I used it for my University project having no Linux experience, but I've probably still got all the setup instructions somewhere.

Ian
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  • Sounds good, but seems a little involved for setting up with running on a windows box (my fault for not mentioning so) – Davy8 Mar 17 '09 at 16:49
  • Only the bridge needs to be running Linux... Therefore you could simply use something like an Unbuntu Live CD with no installation required. You just need to install netem, couple of commands to set the bridge up and you're away... – Ian Mar 17 '09 at 16:54
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Ian's solution seems like a pretty good long term solution, but sounded a little involved for just some quick testing. (finding another machine, hooking it up, possibly setting up router stuff etc)

I ended up just using Net Limiter and randomly set the limit to something stupidly low manually (like 1 byte/sec) and that seems to be sufficient for our needs.

Davy8
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http://snad.ncsl.nist.gov/nistnet/

It's a little complicated to setup, but works very well.

Sam
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