Unix was developed by AT&T in the late 1960s and early 1970s, and it was freely distributed among a number of major universities during those years. When AT&T started charging for Unix, a number of developers tried to create clones of this operating system. One of these clones, Linux, was developed and released in the early 1990s.
Many of these same universities were also developing the network that evolved into the Internet. With current refinements, this makes Linux perhaps the most Internet-friendly network operating system available. The extensive network services available with Linux are not only the tops in their field, but they create one of the most powerful and useful Internet-ready platforms available today at any price.
Currently, Apache is the most popular Web server on the Internet. According to the Netcraft (www.netcraft.com) survey, which tracks the Web servers associated with virtually every site on the Internet, Apache is currently used by more Internet Web sites than all other Web servers combined. Apache is included with RHEL 5.
RHEL 5 also includes a number of other network services. The service that also focuses on Web access is the Squid Proxy Server, which caches frequently used pages locally.
This chapter deals with the basic concepts surrounding the use of these services and a basic level of configuration. In all cases, the assumption is that your network settings are correct and functioning properly. If you're having problems with your network configuration, read Chapter 7.
As for the RHCE exam, you may have to configure or troubleshoot either Apache or Squid. So as you read this chapter and look through the configuration files and exercises, be willing to experiment. And practice, practice, practice what you learn.