Simulate Slow Network in Firefox, Chrome, etc

I assumed it would be difficult to set up network delays at the kernel level so I was looking around at browser extensions. Firefox has Tamper Data and Firefox Throttle, but the former only delays HTTP requests and the latter only works on Windows. Not much available for Chrome yet.

But actually, it is very easy to simulate delays at the kernel level:

$ sudo tc qdisc change dev lo root netem delay 400ms
$ ping localhost
PING violet (127.0.0.1) 56(84) bytes of data.
64 bytes from violet (127.0.0.1): icmp_seq=1 ttl=64 time=800 ms

Increasing latency is the easiest way to see results, but netem can also simulate throttling, packet loss, and other kinds of problems. Way cool!

• netem examples
• tc man page
• tc-htb man page