Chapter 27

27.1	In Figure 27.8, what would change if the client did the active open of the second data connection instead of the server?
A:	Theoretically the connection cannot be established while the socket pair is in the 2MSL wait on either end. Realistically, however, we saw in Section 18.6 that most Berkeley-derived implementations do accept a new SYN for a connection in the TIME_WAIT state.
27.2	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?
A:	These lines are not part of a server reply that begins with a 3-digit reply code, so they cannot be from the server.