To make it a bit more explicit for those not routinely used to digging into web tech, go to the manage page where you can set netspeed and view the HTML source (right click on the background and choose View Source in Chrome). Locate the section around the IP address for which you want to lower netspeed, and grab the “auth_token” hidden input value, a long sequence of hexadecimal numbers with a single hypen at position 2. Copy it to the clipboard and paste it into a scratch document to keep it handy. Then using curl or the address bar in the browser, hit an URL like the following, substituting your own auth token value and matching server IP address:
https://manage.ntppool.org/manage/server/update/netspeed?netspeed=128&auth_token=2-02b7909e180c36216abc5215f48b5ba00fbb3989&server=IP_ADDRESS
The response should look like this if you’re successful:
{“netspeed”:“128 Kbit”,“zones”:“\n\n\nnorth-america\n\nus\n\n\n\n\n\n\n”}
Congratulations, you’ve just set the netspeed to 1/4 of the minimum the dropdown on the webpage allows.