I found two solutions, for mac and windows, if you want to limit the bandwidth of your browser. The best solution for firefox on windows is the add-on “Firefox Throttle“. The developer says it’s useless but I think it is very easy to use. Of course it is much easier of the mac. Just use the local built-in firewall with the commands in the terminal. This limits your port 80 with 8Kbyte/s (just change the values if needed).

sudo ipfw pipe 1 config bw 8KByte/s
sudo ipfw add 1 pipe 1 src-port 80

I already had two reasons for doing this. I didn’t want to steal bandwidth from my office when I downloaded big files and also bandwidth of my wife’s laptop at home to avoid argument With the following command you can delete this “rule”.

sudo ipfw delete 1