Simulate a really poor network connection on your mac (with support for pow.cx backend). Ex. If you expect your users to use your app in a place with poor network (like the meat department of your local grocery store), then this is a way for you to test that sort of connection. This is not scientific in anyway, just a guess.

Rakefile

# Simulate a really poor network connection on your mac  (with support for pow.cx backend)
namespace :network do
  task :status do
    sh 'sudo ipfw show'
  end
  task :bad => [:good] do
    # Add a new pipe
    sh 'sudo ipfw add pipe 1 all from any to any'
    # Configure the pipe to only do 50Kbit/s, with typical delays of 2000ms and 90% packet drop rate!
    sh 'sudo ipfw pipe 1 config bw 50Kbit/s delay 2000ms plr 0.9'
  end
  task :poor => [:good] do
    # Add a new pipe
    sh 'sudo ipfw add pipe 1 all from any to any'
    # Configure the pipe with typical delays of 20ms and 10% packet drop rate!
    sh 'sudo ipfw pipe 1 config delay 20ms plr 0.1'
  end
  task :good do
    # reset
    sh 'sudo ipfw flush'
    # Turn POW back on... cause the flush will seriously flush it...
    sh 'sudo ipfw add 100 fwd 127.0.0.1,20559 tcp from any to me dst-port 80 in'
  end
end