24. a) In Figure 2-16, what will be the value in the destination port number field if a packet arrives for the e-mail applica- tion? b) When the HTTP program on a webserver sends an HTTP response message to a client PC, in what field of what message will it place the value 80? Client 60.171.18.22 Webserver 1.33.17.13 Port 80 60.171.18.22:2707 Destination: 1.33.17.13:80 Source: 1.33.17.13:80 Destination: 60.171.18.22:2707 60.171.18.22:4400 SMTP Server 123.30.17.120 Port 25 Server Programs use Well-Known Port Numbers 0 to 1023) Destination: 123.30.17.120:25 2 Port Number 2700 with the Webserver 4400 with the SMTP Server Clients use Ephemeral Port Numbers (usually 1024 to 4999) FIGURE 2-16 Client Port Numbers and Sockets