To a degree, the response to this might repeat the technology discussion above, focusing on hardware, network architecture, cloud-established tools and much more. Individuals and procedure issue, also.
In a DDoS crisis, there is no replacement for having the right skill sets. Request any or your DNS supplier you might contemplate about the folks on their DDoS mitigation team. Whether they are in house or hired hands, you should know what type of experience they’ve. How precisely do they manage special signatures: TCP SYN attacks, malformed DNS, TCP queries. What sort of training do they get and how frequently do practices run?
Even better, see if they provide simulations of assault answers. Or inquire about meeting our DDoS responders and seeing our SOC. Besides getting the details you need regarding methodologies and their backgrounds, you will create something which pays off after: great communicating.