tcpflow is a program that captures data transmitted as part of TCP connections
(flows), and stores the data in a way that is convenient for protocol analysis 
and debugging. Each TCP flow is stored in its own file. Thus, the typical TCP 
flow will be stored in two files, one for each direction. tcpflow can also 
process stored 'tcpdump' packet flows.

tcpflow is similar to 'tcpdump', in that both process packets from the wire or 
from a stored file. But it's different in that it reconstructs the actual data 
streams and stores each flow in a separate file for later analysis.

tcpflow understands sequence numbers and will correctly reconstruct data 
streams regardless of retransmissions or out-of-order delivery. 
