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

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

   sudo ipfw pipe 1 config bw 500KByte/s
   

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

   sudo ipfw add 1 pipe 1 src-port 80
   

3. 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.