Probing TCP implementations
Douglas E. Comer, John C. Lin · Purdue e-Pubs (Purdue University System) · 1994
In lhis paper, we demonstrate a technique called active probing used to study TCP implementations.Active probing treats a TCP implemenlalion as a black box, and use a set of procedures to probe the black box.By studying the way TCP responds to the probes, one can deduce several characteristics of the implementation.The technique is particularly useful ifTCP source code is unavailable.Active probing operates much like traditional TCP trace analysis.It uses a software tool to capture TCP segments directed toward a particular TCP implementation as well as segments the TCP implemenlation sends in response.It then analyzes the trace data to find patterns that reveal characteristics of the TCP implementation.Unlike trace analysis.however, active probing uses specially designed probing procedures to induce TCP traffic instead of passively monitoring nonnal traffic on lhe network.To demonstrate the technique, the paper shows example probe procedures that examine three aspects of TCP.The results are informative: they reveal implementation flaws.protocol violations, and the details of design decisions in five vendor-supported TCP implementations.The results of our experiment suggest thal active probing can be used to test TCP implementations.