[ Due: N.A ] [ Points: PRICELESS ] [ Date: 2/9/2016] [ Goings, Jesse ] Computer Network Specialist Center For Arts and Technology College Kelowna BC

Transcription

1 [UNIT 1]: <Understanding Apache> This course will be implemented strictly with Linux operating systems Upcoming Topics: MySQL PHP Apache Books required for classes LPICK Foundations of CentOS Apache Apache Basics Making web content available eg: Web Servers We will be focusing on the Linux Software level (The services and what makes it run behind the scenes) According to Netcraft, more than 60% of the world's websites are served by an Apache server Apache started in the mid 1990s as an off shoot of the NCSA HTTPd code, to which numerous patches were applied Today, Apache is developed and maintained under the auspices of the Apache Software Foundation (ASF) which is also home to many various open source software Apart from being free and open source, people choose Apache due to it implements the latest protocols, it is highly configurable, and extensible using third party modules, highly scalable, and high performance Apache being very popular also means there is a wealth of knowledge out there for it! Much of Apache s functionalities are implemented in external modules, called dynamic shared objects (DSOs) An Apache server is normally uses TCP port 80, for secure connections, TCP port 443 is used instead Apache is configured using a large number of configuration directives, Fortunately we do not need to know all of them 1

2 start the service using systemctl start httpd stop the service using systemctl stop httpd create persistent service systemctl enable 2

3 httpdexecute command: ss at grep http wc l (will count lines) The permanent switch allows this firewall exception to talk hold even after reboots (persistent) Filesystem Layout Apache file path locations /etc/httpd/conf/httpd.conf (This is Apache s configuration file) /var/www/html (This is the default location for your web pages) Contexts Contexts define the location where Apache directives may appear, There are four of them 1. Server config : In httpd.conf or the files it includes only 2. Virtual host: Inside <VirtualHost> containers in httpd.conf or included files only 3. Directory: Inside <Directory>, <Location>, and <Files> containers in httpd.confg and included files only 4..htaccess: In.htaccess files only files that are named with a period at the beginning of the file name, these are hidden files Directive names are case insensitive 3

4 Containers Containers are A Container is an object that can execute requests received from a client, and return responses based on those requests. A Container may optionally support a pipeline of Valves that process the request in an order configured at runtime, by implementing the Pipeline interface as well. Absolute paths have / at the beginning (Start at root: /) Relative paths do not have / at the beginning The <Directory> container provides the same functionality as.htaccess files. The difference is that while users can t modify Apache s configurations files, they do control the contents of their own directories <Directory> containers are valid in the server config <Files> are pointing to specific file(s) <Files file.. </Files> The ~ causes Apache to interpret the following string as a regular expression, rather than literally <Files> containers are valid in the server config, virtual host, directory, and.htaccess contexts A regular expression, is a way of using wildcards in a string. adcdef ^adc The ^ specifies that this must be the beginning of the file a?c The? specifies a wildcard meaning any string can be when the? is specified ^\.ht The \ to read as literal, the character(s) off to the right will be read as literal In this example, the file literally means to find.ht <Virtual Host> This applies directives to the specified virtual host, Syntax is: <VirtualHost addr[:port]> </VirtualHost> 4

5 Where addr is the IP address of the virtual host, and the port optionally specifies the port on which Apache listens for this host Containers Note that this directive does not control the ports and IP address on which Apache listens; use Listen directives for that <VirtualHost> containers are valid only in the server config context Directives Apache supports numerous directives for controlling and configuring its behaviour Listen This directive specifies the port(s) on which Apache listens for requests, Syntax Listen [addr:]port Where addr is the ip address and port is the port number. IPv6 addresses must be enclosed in square brackets If addr isn t specified Apache listens on all network interfaces strings encased in [ ] means that it is optional You MUST have at least one Listen directive in the configuration files, otherwise Apache won t work Redirect This tells clients to fetch the requested resource from a different location, Syntax Redirect [status] requested_path [URI] Where status is the status returned to the client in addition to the redirect Errors permanent: Returns status 301 Resource has moved permanently temp: Returns status 302 Resource has moves temporarily seeother: Returns status 303 Resource has been replaced gone: Returns status 410 Resource has been removed 5

6 The requested_path is the absolute pathname of the file or directory for which Apache is to redirect requests. All requests that start with this path are redirected. The Redirect directive is valid in all four contexts ServerAdmin This directive sets the address used in mailto: links on error pages, Syntax ServerAdmin _addr Where _addr is the address to be used Make sure that the address you specify is actually monitored by a person The ServerAdmin directive is valid in the server config and virtual hosts contexts ServerName This directive specifies the server's name and the port on which it listens ServerName FQDN[:port] Where FQDN is the server s Fully Qualified Domain Name Where the port specifies the port number The FQDN must be resolvable by DNS or the hosts file The ServerName directive is valid in the server config and virtual host contexts DocumentRoot This directive specifies the root directory of the server s content hierarchy, Syntax DocumentRoot dir Where dir is the directory s absolute pathname, it can be whatever you like, but remember that the user that Apache runs as must have read access to all files and executable access to all it s directories in the hierarchy 6