This paper will attempt to describe techniques used to discover heavily filtered and firewalled hosts, that will not answer to standard PING responses. It is assumed that the reader has a firm knowledge of the major internet protocols (TCP,IP,UDP,ICMP). . . .
This paper will attempt to describe techniques used to discover heavily filtered and firewalled hosts, that will not answer to standard PING responses. It is assumed that the reader has a firm knowledge of the major internet protocols (TCP,IP,UDP,ICMP). Most other protocols will not be discussed but techniques described here can be applied to many protocols.

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