I'm sure you have heard that there are 13 root servers in the world. This cache file (root hint) provided by internic/IANA http://www.internic.net/zones/named.root should confirm that. So how does these 13 servers brave a DDOS attack . Aparently 6 of the 13 root servers are mirrored using Anycast routing to loadbalance between multiple servers. The F Root server itself has about 37 mirrors in the world. Anycast routing is implemented using BGP by simultaneously announcing the same destination IP range from many different places on the internet. So even though an IP might be registered for a location here in US, if someone announces that a route to the same IP block in Tokyo, hosts in or around that country will try to pick the cheapest route to get to a DNS server. DDOS attacks against root dns servers have happened in the past, and will continue to happen in future. Anycast routing is probably why these "13" DNS servers are still alive today. The next question so