NetFence: Preventing Internet Denial of Service from Inside Out

TL;DR

NetFence introduces a scalable network architecture that effectively prevents DoS attacks by using secure congestion feedback, ensuring fair resource allocation without extensive per-host state at routers.

Contribution

The paper presents a novel congestion policing mechanism and a scalable architecture that guarantees fair bandwidth sharing and reduces router state requirements during DoS attacks.

Findings

Reduces router state from per-host to per-AS

Proves fair resource allocation for legitimate senders

Demonstrates effectiveness through implementation and simulations

Abstract

Denial of Service (DoS) attacks frequently happen on the Internet, paralyzing Internet services and causing millions of dollars of financial loss. This work presents NetFence, a scalable DoS-resistant network architecture. NetFence uses a novel mechanism, secure congestion policing feedback, to enable robust congestion policing inside the network. Bottleneck routers update the feedback in packet headers to signal congestion, and access routers use it to police senders' traffic. Targeted DoS victims can use the secure congestion policing feedback as capability tokens to suppress unwanted traffic. When compromised senders and receivers organize into pairs to congest a network link, NetFence provably guarantees a legitimate sender its fair share of network resources without keeping per-host state at the congested link. We use a Linux implementation, ns-2 simulations, and theoretical analysis to show that NetFence is an effective and scalable DoS solution: it reduces the amount of state maintained by a congested router from per-host to at most per-(Autonomous System).