The web is still small after more than a decade

摘要: Understanding web co-location is essential for various reasons. For instance, it can help one to assess the collateral damage that denial-of-service attacks or IP-based blocking cause availability of co-located sites. However, has been more than a decade since first study was conducted in 2007. The Internet infrastructure changed drastically then, necessitating renewed comprehend nature co-location. In this paper, we conduct an empirical revisit using datasets collected from active DNS measurements. Our results show still small and centralized handful hosting providers. More specifically, find 60% sites are with at least ten other sites---a group comprising less popular contrast, 17.5% mostly served their own servers. Although high degree could make co-hosted vulnerable DoS attacks, our findings increasing trend co-host many serve them well-provisioned content delivery networks (CDN) major providers provide advanced protection benefits. Regardless co-location, analyses block lists indicate does not severe as previously thought.