Setting Up an Internet Site

Linux is well suited for connecting to the Internet and using many of the Internet services. Earlier chapters looked at e-mail and USENET news; this chapter focuses on setting up your Linux machine as a server for FTP, Gopher, WAIS, and the World Wide Web. This chapter looks at the ways you can connect to the Internet. The following chapters then show you how to set up your Linux system as a server for four popular services.

If you only want to use your Linux system to access other servers, you don’t have to worry about any of the material in the next four chapters (although you might want to read this chapter to find out how to connect to the Internet). On the other hand, sharing your system’s resources with others, whether in a local area network, a small circle of friends, or the worldwide Internet community can be most of the fun.

If your Linux system is to offer services such as FTP, WWW, or Gopher to your local area network or to friends connecting by modem, but you don’t want to provide Internet-wide access, you don’t need to worry about connecting to the Internet. You still have to set up the server software, though.

Network Basics

A network topology is the way the cabling is laid out. This doesn’t mean the physical layout (how it loops through walls and floors) but rather how the logical layout looks when viewed in a simplified diagram. You may hear many different names for the type of network you have: ring, bus, star, and so on. They all refer to the shape of the network schematic.

Network Topologies

One of the most widely used network topologies (and the one most often used in medium to large Local Area Networks) is the bus network. A bus network uses a cable to which are attached all the network devices, either directly or through a junction box of some sort. Each device uses a transceiver to connect to the backbone. The manner of attachment depends on the type of bus network, the protocol in use, and the speed of the network. The main cable that is used to connect all the devices is called the backbone. Each end of the backbone (also called a bus) is terminated with a block of resistors or similar electrical device. Most large TCP/IP networks used by Linux are bus topologies.

When a company or organization wants to use the Internet, they must decide whether they want to do it by directly attaching to the Internet system or whether they will use another company to supply the connection. Many companies choose to use another company, called a service provider, because it reduces the amount of equipment, administration, and costs involved.

If the company or organization wants to directly connect (and sometimes when they are using a service provider), they may want to have a unique identification for themselves. For example, ABC Corporation may want to have electronic mail through the Internet addressed to them as "abc.com." The name helps identify the company or organization to the sender.

To obtain one of these unique identifiers called a "domain name", the company or organization sends a request to the body that controls access to the Internet: the Network Information Center, or NIC. If the NIC approves the company’s name, it is added to the Internet database. Domain names must be unique, to prevent confusion.