--delay setting does not impact observed latency on FreeBSD 11.1 on 2.1.0

[cpdohert]

I need to simulate real-world network conditions between a browser running on an Azure VM and an Azure web service. I've inserted a FreeBSD 11.1 VM between them and run throttle-proxy with a --delay setting of 1000.

Running www.speedtest.net, ping, or www.azurespeed.com show no difference in observed latency regardless of what I set --delay to. I have run throttle-proxy both as an unprivileged user and as root.

[mistakster]

@cpdohert, hi!

Yeah, I see the issue. Unfortunately, it’s not that easy to fix it. Let me explain what’s going on.

• CLI command ping doesn’t use proxy at all
• www.speedtest.net uses WebSockets to track a latency
• www.azurespeed.com uses Connection: Keep-Alive header and sends all requests in one connection

My tool applies delay only during initial connection. To simulate real-world network conditions you have to use smarter tools which intercept system network driver and deals with individual IP packets. It might I can apply delay on individual chunk of data. I need to make a series of experiments.

Sorry for inconvenience and thank you for the ideas how to test the tool.