Not quite. There's one sure protection from DDOS actually: scale. For example, Facebook or Google are practically immune from DDOS, since you cannot really overwhelm an infrastructure of that size, even with 100,000s of bots. If you have 10,000s of servers, IP anycast to multiple datacenters, multiple 10Gbps uplinks, you are immune from most DDOSs- they are simply handled like normal traffic fluctuations.