The Internet protocols perform most services with a pair of processes: a client at one end
of the link that actively asks for services, and a server at the other end of the link that
responds to requests and performs the requested activity. These terms are also used to
describe computer systems, but here we’re talking about processes, not systems. In this
chapter, we’ll look at the client side of things, and in Chapter 25, Basic network access:
servers we’ll look at the corresponding servers....