(cat /etc/pf.conf && echo "dummynet-anchor \"mop\"" && echo "anchor \"mop\"") | sudo pfctl -f -
echo "dummynet in quick proto tcp from any to any port 5001 pipe 1" | sudo pfctl -a mop -f -
sudo dnctl pipe 1 config bw 1Mbit/s

To undo...

sudo dnctl -q flush
sudo pfctl -f /etc/pf.conf

Observe traffic is now shaped to 100Mbit/s:

iperf  -s -D # Run as Daemon (-D)
iperf -c localhost -t 5 

---

Client connecting to localhost, TCP port 5001 TCP window size: 144 KByte (default)

[ 5] local 127.0.0.1 port 59573 connected with 127.0.0.1 port 5001 [ ID] Interval Transfer Bandwidth [ 5] 0.0- 5.0 sec 60.5 MBytes 101 Mbits/sec

I perf

Setup the server:

iperf -s

Run the client against the server for 7 seconds:

iperf -c localhost -t 7

You should get a throughput in (GMk)bits/sec

• https://gist.github.com/tracphil/4353170