This also seems to be unknown even to some university professors, who I've seen set up lab exercises using actual CloudFlare ASNs and IPs on a simulator connected to the open Internet. Not exactly dangerous as it would obviously get filtered, but still really bad form.
[1] https://tools.ietf.org/html/rfc5737 [2] https://tools.ietf.org/html/rfc3849 [3] https://tools.ietf.org/html/rfc5398
This also seems to be unknown even to some university professors, who I've seen set up lab exercises using actual CloudFlare ASNs and IPs on a simulator connected to the open Internet. Not exactly dangerous as it would obviously get filtered, but still really bad form.