Abstract:
In computer networks, a proxy server is a server that may be a computer system or an application that acts as an intermediary for requests from clients seeking resources from other servers. In this paper, it mainly focuses to resist proxy-based DDOS attacks. It extracts the behavior features of traffic from proxy to server based on temporal and spatial locality. A hidden semi-markov model is used to describe traffic behavior of proxy to server. Here, it assessed the short-term behavior for improving quality of services of normal users. It converting suspicious sequence into normal one by discarding most illegimate request, instead of discarding entire sequence.

Keywords: Traffic analysis, traffic modelling, DDOS attack, detection of attackers and response.