I won't kid you, sockets are a complicated subject. Fortunately, you only have to learn about a small subset of the socket functionality in order to use the high-level protocols. A list of the high-level protocols that you can use is given below with the protocol number in brackets. Lets you connect to a host and use it as if you were a directly connected terminal Each protocol is also called a service. Hence the term, mail server or ftp server.
Incoming conversations arrive at something called a port.
In this chapter, we take a quick look at sockets, and then turn our attention to examples that use them. You see how to send and receive mail.