How can I limit bandwidth for a specific port/app in OS X 10.10 Yosemite?
For port 8333:

Create the anchor for pf to use:

(cat /etc/pf.conf &amp;&amp; echo "dummynet-anchor \"customRule\"" &amp;&amp; echo "anchor \"customRule\"") | sudo pfctl -f -


Create the PIPE to send the desired port to your dummynet anchor:

echo "dummynet in quick proto tcp from any to any port 8333 pipe 1" | sudo pfctl -a customRule -f -


Then set the desired speed for the pipe you created: (E.X: limit to 10mb/s)

sudo dnctl pipe 1 config bw 10Mbit/s


http://mop.koeln/blog/2015/06/01/Limiting-bandwidth-on-Mac-OS-X-yosemite/

I have been using a app called Murus, It claims to do this and much more but I have yet to get it to work on the free version for port throttling.  Very powerful otherwise of a gui app.