APACHEAn open source web server. Mostly for Unix, Linux and Solaris platformsApache is the most popular web server on the net.It is very secure, fast, and reliable.The name "Apache" derives from the word "patchy"that the Apache developers used to describe earlyversions of their software.
FEATURESImplements many frequently requested features, including:DBM databases for authenticationCustomized responses to errors and problemsVirtual HostsMultiple DirectoryIndex directivesIt has been tested thoroughly by both developers and users.
APACHE WEB SERVERIt provides a full range of Web server features, including CGI, SSL, and virtual domains.It also supports plug-in modules for extensibility.
The Apache Web Server hasHTTPIISSSLThe Apache Web server has been ported to Windows and other network operating systems (NOS). The Apache HTTP Server is web server software notable for playing a key role in the initial growth of the World Wide Web.
HTTPHTTP is an Hypertext Transfer Protocol.It provides a standard for Web browsers and servers to communicate. The definition of HTTP is a technical specification of a network protocol that software must implement.HTTP is an application layer network protocol built on top of TCP.
HTTP clients (such as Web browsers) and servers communicate via HTTP request and response messages. The three main HTTP message types are GET, POST, and HEAD.HTTP utilizes TCP port 80 by defaultThough other ports such as 8080 can alternatively be used.
The HTTP also includesARPAddress Resolution ProtocolDHCPDynamic Host Configuration ProtocolFTPFile Transfer Protocol
ARPARP converts an Internet Protocol (IP) address to its corresponding physical network address. ARP is a lowlevel network protocol, operating at Layer 2 of the OSI model.ARP is implemented usually in the device drivers of network operating systems. It is most commonly seen on Ethernet networks, ATM, Token Ring, and other physical networks.
DHCPDHCP allows a computer to join an IP-based network without having a pre-configured IP address.DHCP is a protocol that assigns unique IP addresses to devices, then releases and renews these addresses as devices leave and re-join the network.
FTPFTP allows you to transfer files between two computers on the Internet. FTP is a simple network protocol based on Internet Protocol.
SSLSecure Sockets Layer SSL security technology helps to improve the safety of Internet communications. SSL is a standard for encrypted client/server communication between network devices.A network protocol, SSL runs on top of TCP/IP.
SSL utilizes several standard network security techniques including public keys, symmetric keys, and certificates. Web sites commonly use SSL to guard private information such as credit card numbers.
CONFIGURATIONInstead of using a pointandclick graphic user interface (GUI) or Windows Registry keys as most other modern software packages, Apache generally relies on simple text files for its configuration settings.
Configuring FilesApache uses a system of three text files for managing its configuration data. All three of these files (almost always) appear in Apaches ./conf directory and are designed to be edited by system administrators: httpd.conf for general settings srm.conf for resource settings access.conf for security settings
In the most recent versions of Apache, the default installation has changed. The httpd.conf is treated as the "master" configuration file and it contains all of the settings. Both srm.conf and access.conf still exist in the installation, but they contain no settings and are empty except for some comments.
Like many UNIXstyle programs, Apache will not reread the .conf files after the Web server starts running. After making changes, an administrator must restart Apache for the new settings to take effect.
Inside Httpd.confThe httpd.conf contained general settings such as the ServerName and Port number. These entries appear as follows in the file: ServerName compnetworking.about.com Port 80 The term "httpd" stands for HTTP Daemon.
This file contains a number of other entries (technically called directives), but for most of these, modifications are optional. The most useful of these entries is ServerAdmin it allows the administrator to set the email address that will be displayed on error pages (such a "404 pages") in the clients browser, giving users a way to contact someone if a site problem occurs: ServerAdmin firstname.lastname@example.org
Running ApacheApache does not run from the inetd super server as many other network servers do. It is configured to run standalone for better performance for incoming HTTP requests from client web browsers. A shell script wrapper is included to make starting, stopping, and restarting the server as simple as possible. To start up Apache for the first time, just run:# /usr/local/sbin/apachectl start
You can stop the server at any time by typing:# /usr/local/sbin/apachectl stopAfter making changes to the configuration file for any reason, you will need to restart the server:# /usr/local/sbin/apachectl restartTo restart Apache without aborting current connections, run:# /usr/local/sbin/apachectl graceful
*The family of .conf files supports most, but not all of Apaches configuration options. *Other important mechanisms for managing an Apache Web server include the .htaccess file, the mime.types file, and the family of log files.