TCP/IP Illustrated, Vol. 1: The Protocols (Addison-Wesley Professional Computing Series)

In Figure 27.8, what would change if the client did the active open of the second data connection instead of the server?

In the FTP client examples in this chapter we added the notation to lines such as

local: hello.c remote: hello.c 42 bytes received in 0.0037 seconds (11 Kbytes/s)

that the lines were output by the client. Without looking at the source code, how are we certain these are not from the server?