Web and Application Server Fundamentals

Before you learn how to set up a Web server and an application server, it's important to understand what these servers do and where they can be located.

A Web server is software that serves files in response to an HTTP request from a Web browser. If the requested file contains only HTML, the Web server sends ("serves") the file to the Web browser. If the file contains server-side code, the Web server forwards the page to an application server.

An application server is software that processes server-side code and outputs an HTML file. The HTML file is sent to the Web server, which then serves the HTML page to the requesting Web browser.

Web servers and application servers can be located on either a remote or local computer. See Table 1.1 for a comparison of the advantages and disadvantages of both.

Table 1.1.

Local vs. Remote Server Locations
SERVER LOCATION	ADVANTAGES	DISADVANTAGES
Local	You can quickly preview and test pages locally without an Internet connection or time lag for file upload.	Your computer is vulnerable to security risks when you're online.
	You are the server administrator and control access to the server.	You must spend time dealing with server maintenance, particularly security.
	You get hands-on experience working with server technologies.	You are your own tech support.
		You eventually will need to upload your files to a remote server so they can be viewed online.
Remote	You have a server administrator who deals with server set up, server maintenance, and server security.	You must be online to access the server. You must upload files to preview dynamic pages.
	You have tech support for server issues.	If you need to troubleshoot your pages or make changes, you must upload the pages every time you make a change.

Tips

• If you are using your employer's computer for Web-application development, you'll likely need to use a remote server. Because of security concerns, most server administrators won't allow Web server installation on their computers.

• If you install a local Web server, make sure you're using a firewall.

• If you decide that you want to use a local server for your Web and application servers, the first step is to set up a Web server on your computer (see the next section).

• If you've decided that a remote server is the way to go, you'll need a remote hosting account for your site, if you don't already have one. Make sure you choose a remote host that supports your choice of application server (see "Choosing an Application Server," later in this chapter, for more information).