Naturally, there must be a timeout period after which the server initiates teardown of the TCP connection. Here we have an inital status line, six header lines, and the entity body. Requested document does not exist on this server. Try a nonexistent user or filename, and see what happens. HTTP server simplifies server design, but makes it hard to identify users.
Client contacts a Web site for the first time.
The server does not know the username of the user, but that the user made a specific request one week ago. If server wants to remember a user's preferences, so it can provide targeted advertising, it can set a cookie.