The infrastructure described in this chapter uses the client/server model to provide a public mail service through the telephone line. In this configuration, we (the poeple building the infrastructure) provide the information you (the person using the infrastructure) need to know in order to establish a dial-up connection from the client computer to the server computer through the telephone line. The infrastructure described in this chapter is made available to you free of charge, however, you should know that maintaining it costs both money and time. For example, for each hour the server computer is on production there is an electrical consume that need to be paid every month. Likewise, each call that you establish from the client computer to the server computer will cost you money, based on the location you made the call from and the time you spend connected. In this manual, by dial-up connection we mean the action of dialing-up a server computer from a client computer through a Modem attached to the telephone line. In this infrastructure, dial-up connections are always established from the client computer to the server computer and never the other way around. The main purpose of a client computer to establish a dial-up connection with the server computer will be using one or more Internet services provided in the server computer. In order for the server computer to answer telephone calls, it is required to install a Modem device in it (see ). Once the Modem device has been installed, you need to install and configure both mgetty and pppd programs. The mgetty program must be run by init daemon in order to take control over the Modem device. By default, inside &TCD; (release 5.5), mgetty isn't configured to start with init daemon so you need to do it yourself (see ...). Later, for attending connection requests, you need to configure mgetty to use the pppd program, so the Point-to-Point Protocol (PPP) can be talked and IP packages can be interchanged between the client computer and the server computer. Later, you need to configure pppd to adjust it to your needs (see ...). Once you've configured both mgetty and pppd programs, the server computer should be ready to attend incoming calls. The remaining of this chapter describes the way incoming calls are attended by the server computer once they have arrived to its Modem device.