Protecting the DNS from Routing Attacks: Two Alternative Anycast Implementations

The domain name system is a critical piece of the Internet and supports most Internet applications. Because it's organized in a hierarchy, its correct operation depends on the availability of just a few servers at the hierarchy's upper levels. These backbone servers are vulnerable to routing attacks in which adversaries controlling part of the routing system try to hijack the server address space. Using routing attacks in this way, an adversary can compromise the Internet's availability and integrity at a global scale. In this article, the authors evaluate the relative resilience to routing attacks of two alternative anycast DNS implementations. The first operates at the network layer and the second at the application layer. The evaluation informs fundamental DNS design decisions and an important debate on the routing architecture of the Internet.

The DNS and Interdomain Routing

Before discussing DNS threats and countermeasures, let's look at the DNS itself, an application-layer service that relies on the network layer to connect clients to its servers. We also provide background on the interdomain routing system that establishes the network-layer paths the DNS uses.