APACHEThe Apache HTTP Server, commonly referred to as Apache, is web server software notable for playing a key role in the initial growth of the World Wide Web. In 2009 it became the first web server software to surpass the 100 million web site milestone. Apache was the first viable alternative to the Netscape Communications Corporation web server (currently known as Sun Java System Web Server), and has since evolved to rival other Unix-based web servers in terms of functionality and performance. The majority of web servers using Apache run a Unix-like operating system.[citation needed]

Apache is developed and maintained by an open community of developers under the auspices of the Apache Software Foundation. The application is available for a wide variety of operating systems, including Unix, GNU, FreeBSD, Linux, Solaris, Novell NetWare, Mac OS X, Microsoft Windows, OS/2, TPF, and eComStation. Released under the Apache License, Apache is characterized as open source software.

Since April 1996 Apache has been the most popular HTTP server software in use. As of February 2010[update] Apache served over 54.46% of all websites and over 66% of the million busiest.

FEATURESFeatures

Apache supports a variety of features, many implemented as compiled modules which extend the core functionality. These can range from server-side programming language support to authentication schemes. Some common language interfaces support Perl, Python, Tcl, and PHP. Popular authentication modules include mod_access, mod_auth, mod_digest, and mod_auth_digest, the successor to mod_digest. A sample of other features include SSL and TLS support (mod_ssl), a proxy module (mod_proxy), a URL rewriter (also known as a rewrite engine, implemented under mod_rewrite), custom log files (mod_log_config), and filtering support (mod_include and mod_ext_filter).

Popular compression methods on Apache include the external extension module, mod_gzip, implemented to help with reduction of the size (weight) of web pages served over HTTP. ModSecurity is an open source intrusion detection and prevention engine for web applications. Apache logs can be analyzed through a web browser using free scripts such as AWStats/W3Perl or Visitors.

Virtual hosting allows one Apache installation to serve many different actual websites. For example, one machine with one Apache installation could simultaneously serve www.example.com, www.test.com, test47.test-server.test.com, etc.

USEApache is primarily used to serve both static content and dynamic Web pages on the World Wide Web. Many web applications are designed expecting the environment and features that Apache provides.

Apache is redistributed as part of various proprietary software packages including the Oracle Database and the IBM WebSphere application server. Mac OS X integrates Apache as its built-in web server and as support for its WebObjects application server. It is also supported in some way by Borland in the Kylix and Delphi development tools. Apache is included with Novell NetWare 6.5, where it is the default web server. Apache is included with many Linux distributions.

Apache is used for many other tasks where content needs to be made available in a secure and reliable way. One example is sharing files from a personal computer over the Internet. A user who has Apache installed on their desktop can put arbitrary files in Apache's document root which can then be shared.

Programmers developing web applications often use a locally installed version of Apache in order to preview and test code as it is being developed.

Microsoft Internet Information Services (IIS) is the main competitor to Apache, followed by Sun Microsystems' Sun Java System Web Server and a host of other applications such as Zeus Web Server.

PERFORMANCEAlthough the main design goal of Apache is not to be the "fastest" web server, Apache does have performance comparable to other "high-performance" web servers. Instead of implementing a single architecture, Apache provides a variety of MultiProcessing Modules (MPMs) which allow Apache to run in a process-based, hybrid (process and thread) or event-hybrid mode, to better match the demands of each particular infrastructure. This implies that the choice of correct MPM and the correct configuration is important. Where compromises in performance need to be made, the design of Apache is to reduce latency and increase throughput, relative to simply handling more requests, thus ensuring consistent and reliable processing of requests within reasonable time-frames.

HOW TO INSTALL APACHE IN LINUX

Download Apache

I recommend downloading the latest stable release. At the time of this writing, that was Apache 2.0. The best place to get Apache is from the Apache HTTP Server download site. Download the sources appropriate to your system. Binary releases are available as well.

Extract the Files

Once you've downloaded the files you need to uncompress them and untarring: gunzip -d httpd-2_0_NN.tar.gz tar xvf httpd-2_0_NN.tarThis creates a new directory under the current directory with the source files.

HOW TO CONFIGURE

Once you've got the files, you need to tell your machine where to find everything by configuring the source files. The easiest way is to accept all the defaults and just type: ./configure

Of course, most people don't want to accept just the default choices. The most important option is the prefix= option. This specifies the directory where the Apache files will be installed. You can also set specific environment variables and modules. Some of the modules I like to have installed are:

* mod_alias - to map different parts of the URL tree * mod_include - to parse Server Side Includes * mod_mime - to associate file extensions with its MIME-type * mod_rewrite - to rewrite URLs on the fly * mod_speling (sic) - to help your readers who might misspell URLs * mod_ssl - to allow for strong cryptography using SSL * mod_userdir - to allow system users to have their own Web page directories

CONFIGURE

Customize

Assuming that there were no problems, you are ready to customize your Apache configuration. This really just amounts to editing the httpd.conf file. This file is located in the PREFIX/conf directory. I generally edit it with vi: vi PREFIX/conf/httpd.confNote: you'll need to be root to edit this file.

This is the main Apache HTTP server configuration file. It contains the configuration directives that give the server its instructions. See <URL:http://httpd.apache.org/docs/2.2> for detailed information.In particular, see <URL:http://httpd.apache.org/docs/2.2/mod/directives.html> for a discussion of each configuration directive.

Do NOT simply read the instructions in here without understanding what they do. They're here only as hints or reminders. If you are unsure consult the online docs. You have been warned.

Configuration and logfile names: If the filenames you specify for many of the server's control files begin with "/" (or "drive:/" for Win32), the server will use that explicit path. If the filenames do *not* begin with "/", the value of ServerRoot is prepended -- so "logs/foo.log" with ServerRoot set to "/opt/lampp" will be interpreted by the server as "/opt/lampp/logs/foo.log".

ServerRoot: The top of the directory tree under which the server's configuration, error, and log files are kept.

Do not add a slash at the end of the directory path. If you point ServerRoot at a non-local disk, be sure to point the LockFile directiveat a local disk. If you wish to share the same ServerRoot for multiple httpd daemons, you will need to change at least LockFile and PidFile.

ServerRoot "/opt/lampp"

Listen: Allows you to bind Apache to specific IP addresses and/or ports, instead of the default. See also the <VirtualHost> directive.

Change this to Listen on specific IP addresses as shown below to prevent Apache from glomming onto all bound IP addresses.

Listen 12.34.56.78:80Listen 80

'Main' server configuration

The directives in this section set up the values used by the 'main' server, which responds to any requests that aren't handled by a <VirtualHost> definition. These values also provide defaults for any <VirtualHost> containers you may define later in the file.

All of these directives may appear inside <VirtualHost> containers, in which case these default settings will be overridden for the virtual host being defined.

ServerAdmin: Your address, where problems with the server should be e-mailed. This address appears on some server-generated pages, such as error documents. e.g. admin@your-domain.com

ServerAdmin you@example.com

DocumentRoot: The directory out of which you will serve your documents. By default, all requests are taken from this directory, but symbolic links and aliases may be used to point to other locations.

DocumentRoot "/opt/lampp/htdocs"

Each directory to which Apache has access can be configured with respect to which services and features are allowed and/or disabled in that directory (and its subdirectories).

First, we configure the "default" to be a very restrictive set of features.

<Directory /> Options FollowSymLinks AllowOverride None #XAMPP #Order deny,allow #Deny from all</Directory>

DirectoryIndex: sets the file that Apache will serve if a directory is requested.

<IfModule dir_module> #DirectoryIndex index.html # XAMPP DirectoryIndex index.html index.html.var index.php index.php3 index.php4</IfModule>

The following lines prevent .htaccess and .htpasswd files from being viewed by Web clients.

<FilesMatch "^\.ht"> Order allow,deny Deny from all</FilesMatch>

DefaultType: the default MIME type the server will use for a document if it cannot otherwise determine one, such as from filename extensions. If your server contains mostly text or HTML documents, "text/plain" is a good value. If most of your content is binary, such as applications or images, you may want to use "application/octet-stream" instead to keep browsers from trying to display binary files as though they are text.

DefaultType text/plain<IfModule mime_module> TypesConfig points to the file containing the list of mappings from filename extension to MIME-type. TypesConfig etc/mime.types

AddType allows you to add to or override the MIME configuration file specified in TypesConfig for specific file types. AddType application/x-gzip .tgz AddEncoding allows you to have certain browsers uncompress information on the fly. Note: Not all browsers support this.

EnableMMAP and EnableSendfile: On systems that support it, memory-mapping or the sendfile syscall is used to deliver files. This usually improves server performance, but must be turned off when serving from networked-mounted filesystems or if support for these functions is otherwise broken on your system.

EnableMMAP offEnableSendfile off

Supplemental configuration

The configuration files in the etc/extra/ directory can be included to add extra features or to modify the default configuration of the server, or you may simply copy their contents here and change as necessary.

Server-pool management (MPM specific)Include etc/extra/httpd-mpm.conf

Multi-language error messagesInclude etc/extra/httpd-multilang-errordoc.conf

Fancy directory listingsInclude etc/extra/httpd-autoindex.conf

Language settingsInclude etc/extra/httpd-languages.conf

User home directoriesInclude etc/extra/httpd-userdir.conf

Real-time info on requests and configurationInclude etc/extra/httpd-info.conf

Virtual hostsInclude etc/extra/httpd-vhosts.conf

Local access to the Apache HTTP Server ManualInclude etc/extra/httpd-manual.conf

Distributed authoring and versioning (WebDAV)Include etc/extra/httpd-dav.conf

Various default settingsInclude etc/extra/httpd-default.conf

Secure (SSL/TLS) connections<IfModule ssl_module> XAMPP<IfDefine SSL>Include etc/extra/httpd-ssl.conf</IfDefine></IfModule>

Note: The following must must be present to support starting without SSL on platforms with no /dev/random equivalent but a statically compiled-in mod_ssl.

<IfModule ssl_module>SSLRandomSeed startup builtinSSLRandomSeed connect builtin</IfModule>

XAMPP Include etc/extra/httpd-xampp.conf

Test Your Server

Open a Web browser on the same machine and type http://localhost/ in the address box. You should see a page similar to the one in the partial screen shot above. Specifically, it will say in big letters "Seeing this instead of the website you expected?" This is good news, as it means your server installed correctly.

Start Editing/Uploading Pages

Once your server is up and running you can start posting pages. Have fun building your Web site.

Thank you