Getting Started

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If you're completely new to the Apache HTTP Server, or even to running +a website at all, you might not know where to start, or what questions to +ask. This document walks you through the basics.

Clients, Servers, and URLs
Hostnames and DNS
Configuration Files and Directives
Web Site Content
Log Files and Troubleshooting
What's next?

Clients, Servers, and URLs

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+Addresses on the Web are expressed with URLs - Uniform Resource Locators +- which specify a protocol (e.g. http), a servername (e.g. +www.apache.org), a URL-path (e.g. +/docs/current/getting-started.html), and possibly a query +string (e.g. ?arg=value) used to pass additional +arguments to the server. +

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A client (e.g., a web browser) connects to a server (e.g., your Apache HTTP Server), +with the specified protocol, and makes a request for a resource using the +URL-path.

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The URL-path may represent any number of things on the server. It may +be a file (like getting-started.html) a handler (like server-status) or some kind of program +file (like index.php). We'll discuss this more below in +the Web Site Content section.

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+The server will send a response consisting of a status +code and, optionally, a response body. +The status code indicates whether the request was successful, and, if not, what +kind of error condition there was. This tells the client what it should +do with the response. You can read about the possible response codes in +HTTP Server +wiki.

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Details of the transaction, and any error conditions, are written to +log files. This is discussed in greater detail below in the Logs Files and Troubleshooting section.

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Hostnames and DNS

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In order to connect to a server, the client will first have to resolve +the servername to an IP address - the location on the Internet where the +server resides. Thus, in order for your web server to be reachable, it +is necessary that the servername be in DNS.

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If you don't know how to do this, you'll need to contact your network +administrator, or Internet service provider, to perform this step for +you.

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More than one hostname may point to the same IP address, and more +than one IP address can be attached to the same physical server. Thus, you +can run more than one web site on the same physical server, using a +feature called virtual hosts.

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If you are testing a server that is not Internet-accessible, you +can put host names in your hosts file in order to do local resolution. +For example, you might want to put a record in your hosts file to map a +request for www.example.com to your local system, for +testing purposes. This entry would look like:

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+127.0.0.1 www.example.com +

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A hosts file will probably be located at /etc/hosts or +C:\Windows\system32\drivers\etc\hosts.

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You can read more about the hosts file at Wikipedia.org/wiki/Hosts_(file), and +more about DNS at Wikipedia.org/wiki/Domain_Name_System.

Configuration Files and Directives

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The Apache HTTP Server is configured via simple text files. +These files may be located any of a variety of places, depending on how +exactly you installed the server. Common locations for these files may +be found in +the httpd wiki. If you installed httpd from source, the default +location of the configuration files is +/usr/local/apache2/conf. The default configuration file is +usually called httpd.conf. This, too, can vary in +third-party distributions of the server.

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The configuration is frequently broken into multiple smaller files, +for ease of management. These files are loaded via the Include directive. The names or locations of +these sub-files are not magical, and may vary greatly from one +installation to another. Arrange and subdivide these files as +makes the most sense to you. If the file arrangement +you have by default doesn't make sense to you, feel free to rearrange it.

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The server is configured by placing configuration directives in these +configuration files. A directive is a keyword followed by one or more +arguments that set its value.

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The question of "Where should I put that +directive?" is generally answered by considering where you want a +directive to be effective. If it is a global setting, it should appear +in the configuration file, outside of any <Directory>, <Location>, <VirtualHost>, or other section. If it is to +apply only to a particular directory, then it should go inside a +<Directory> section referring to +that directory, and so on. See the Configuration +Sections document for further discussion of these sections.

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In addition to the main configuration files, certain directives may go in +.htaccess files located in the content directories. +.htaccess files are primarily for people who do not have +access to the main server configuration file(s). You can read more about +.htaccess files in the .htaccess howto.

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Web Site Content

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Web site content can take many different forms, but may be broadly +divided into static and dynamic content.

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Static content is things like HTML files, image files, CSS files, +and other files that reside in the filesystem. The DocumentRoot directive specifies where in your +filesystem you should place these files. This directive is either set +globally, or per virtual host. Look in your configuration file(s) to +determine how this is set for your server.

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Typically, a document called index.html will be served +when a directory is requested without a file name being specified. For +example, if DocumentRoot is set to +/var/www/html and a request is made for +http://www.example.com/work/, the file +/var/www/html/work/index.html will be served to the +client.

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Dynamic content is anything that is generated at request +time, and may change from one request to another. There are numerous +ways that dynamic content may be generated. Various handlers are available to generate content. CGI programs may be written to generate +content for your site.

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Third-party modules like mod_php may be used to write code that does a +variety of things. Many third-party applications, written using a +variety of languages and tools, are available for download and +installation on your Apache HTTP Server. Support of these third-party +things is beyond the scope of this documentation, and you should find +their documentation or other support forums to answer your questions +about them.

Log Files and Troubleshooting

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As an Apache HTTP Server administrator, your most valuable assets are +the log files, and, in particular, the error log. Troubleshooting any +problem without the error log is like driving with your eyes closed.

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The location of the error log is defined by the ErrorLog directive, which may be set globally, +or per virtual host. Entries in the error log tell you what went wrong, +and when. They often also tell you how to fix it. Each error log message +contains an error code, which you can search for online for even more +detailed descriptions of how to address the problem. You can also +configure your error log to contain a log ID which you can then +correlate to an access log entry, so that you can determine what request +caused the error condition.

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You can read more about logging in the logs +documentation.

What's next?

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Once you have the prerequisites under your belt, it's time to move +on.

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This document covers only the bare basics. We hope that this gets you +started, but there are many other things that you might need to +know.

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Getting Started

See also

Clients, Servers, and URLs

Hostnames and DNS

Configuration Files and Directives

Web Site Content

Log Files and Troubleshooting

What's next?

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