Denodo does not have any specific mechanism for DDoS protection, because that is a specialization covered by third party solutions that would exist outside and around it, not in it. Ideally, such a solution would depend on the interface you would be using to expose the web interface externally, and would be hardware based.
Since Denodo is more of a data solution than a network one, I would consult your ISPs on what protections they offer, and if you’re utilizing Denodo on AWS, they apparently have DDoS protection solutions as well. You could also look into hardware solutions, which are the typical way to handle DDoS.
Hope this helps!