How can I limit my download bandwidth?
OSX provides ipfw to define custom firewall rules. Using this tool you can create a pipe with limited bandwidth.

When you assign the throttled pipe to a specific port, this port's bandwidth is limited.

Quick How-To


Create a pipe "1" limited to 500KBytes/s via

sudo ipfw pipe 1 config bw 500KByte/s

Guide all network traffic of port 80 through pipe "1" using

sudo ipfw add 1 pipe 1 src-port 80

When you don't need the pipe anymore, remove it from the port using

sudo ipfw delete 1



Other


If you want to set higher traffic barriers, you can use MByte/s
Port 80: standard port for unencrypted http traffic. This port is used for most browsing and downloading. You should be fine with this in most cases.
Port 443: standard port for SSL encrypted https traffic.