You can control access to the bwctl server via the file /etc/bwctl-server/bwctl-server.limits.
By default, the perfSONAR toolkit allows access from anywhere, and limits TCP tests to 60 seconds, and UDP tests to 100Mbps and 30 seconds.
ESnet generates a nightly update of bwctl-server.limits that allows testing from all Research and Education networks around the world, and nothing else.
Information on how to use this file is available at Limiting Tests to R&E Networks Only.