Digging Deeper Into TCP/IP

This paper takes a close look at TCP/IP as a reference for the security professional. Its goal is to consolidate information from numerous sources into one place and to go deeper into the client/server relationship. It explores basic TCP/IP concepts such as encapsulation, IP and TCP definitions, client/server connections, and discusses less well-known concepts such as state. It concludes with an illustration of an entire TCP session (Figure 10), including absolute sequence and acknowledgement numbers, state identification, and client and server responses.