How to simulate slow internet connections on the mac

Question

What's a good software solution to slow down internet connections on the mac for testing and simulations?

My primary need is when testing code in the iPhone / iOS simulator, so slowing down the connection for specific applications or processes would be great.

Answer 1

Apple has made a very handy official tool to slow down the network on the mac for testing.

It's called the Network Link Conditioner and it's a free download of Xcode for Lion users. Most older versions of Xcode before version 4.3.2 embedded a copy of this tool. Now, you use Xcode to download it directly in a similar manner to the iOS simulators and developer documentation.

There are 11 built in profiles from a Lossy Edge network with 400ms delay to a cable modem. If you need other limits, you can also use ipfw yourself as described in Craig Hockenberry's article slow ride, make it easy It also mentions the Speed Limit panel by Mike Schrag that is a smaller download than Xcode, but has fewer options than Apple's tool.

It slows down the entire network stack, so you can't throttle on a per app basis without doing things like install lion in a virtual machine and set that VM with a throttled stack.

Answer 2

Speed Limit is a System Preferences pane for intentionally and selectively slowing down specific ports and domains.

Answer 3

OSX provides ipfw to define custom firewall rules. Using this tool you can create a pipe with limited bandwidth.

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.

Answer 4

If you only need throttling for Web development, I can wholeheartedly recommend Charles. It's an excellent tool for debugging HTTP applications anyway, and among its many features, it's got a Throttle option. The software isn't cheap, but it does an excellent job.

Answer 5

If your xcode 4.2.x deleted your /Developer then you can download it again by

Xcode > Open Developer Tool > More Developer Tools

Answer 6

There is also this tutorial on how to slow down your network.

Answer 7

I think u need to have DNS configration check tutorial from here