Denial of service (DoS) attacks are a large and increasing threat
to the Internet community. In this paper, we propose using a
distributed approach to DoS defense. Our architecture leverages the
properties of a wide-area overlay network to isolate clusters of
attackers while denying access to a minimal amount of legitimate users.
This is done by collaborating with other members of a structured peer
to peer network, which is inherently collaborative. Our results show
that such our approach is effective at both detection and suppression
of a DoS attack.