Setup and configuration of apache2 server

preface

This article mainly introduces the construction and configuration of apache2 server under linux, which has a definite reference value. Let's learn about it from now on.

Complete the following steps

The first is to download the bag, of course:

myths@myths-X450LD:~$ sudo apt-get install apache2

After loading, it can be used. Enter the local echo address 127.0.0.1 or localhost in the address bar to enter the default interface.

The default interface is, of course, the apache2 specification interface. In fact, many cases do not need to find help on the Internet documentation, almost all software will come with instructions, just a little long, we are lazy to read. But a lot of the important stuff is in there, like the default interface for apache2:

Ubuntu Logo Apache2 Ubuntu Default Page
It works!
This is the default welcome page used to test the correct operation of the Apache2 server after installation on Ubuntu systems. It is based on the equivalent page on Debian, from which the Ubuntu Apache packaging is derived. If you can read this page, it means that the Apache HTTP server installed at this site is working properly. You should replace this file (located at /var/www/html/index.html) before continuing to operate your HTTP server.
If you are a normal user of this web site and don't know what this page is about, this probably means that the site is currently unavailable due to maintenance. If the problem persists, please contact the site's administrator.
Configuration Overview
Ubuntu's Apache2 default configuration is different from the upstream default configuration, and split into several files optimized for interaction with Ubuntu tools. The configuration system is fully documented in /usr/share/doc/apache2/README.Debian.gz. Refer to this for the full documentation. Documentation for the web server itself can be found by accessing the manual if the apache2-doc package was installed on this server.
The configuration layout for an Apache2 web server installation on Ubuntu systems is as follows:
/etc/apache2/
|-- apache2.conf
|  `-- ports.conf
|-- mods-enabled
|  |-- *.load
|  `-- *.conf
|-- conf-enabled
|  `-- *.conf
|-- sites-enabled
|  `-- *.conf
apache2.conf is the main configuration file. It puts the pieces together by including all remaining configuration files when starting up the web server.
ports.conf is always included from the main configuration file. It is used to determine the listening ports for incoming connections, and this file can be customized anytime.
Configuration files in the mods-enabled/, conf-enabled/ and sites-enabled/ directories contain particular configuration snippets which manage modules, global configuration fragments, or virtual host configurations, respectively.
They are activated by symlinking available configuration files from their respective *-available/ counterparts. These should be managed by using our helpers a2enmod, a2dismod, a2ensite, a2dissite, and a2enconf, a2disconf . See their respective man pages for detailed information.
The binary is called apache2\. Due to the use of environment variables, in the default configuration, apache2 needs to be started/stopped with /etc/init.d/apache2 or apache2ctl. Calling /usr/bin/apache2 directly will not work with the default configuration.
Document Roots
By default, Ubuntu does not allow access through the web browser to any file apart of those located in /var/www, public_html directories (when enabled) and /usr/share (for web applications). If your site is using a web document root located elsewhere (such as in /srv) you may need to whitelist your document root directory in /etc/apache2/apache2.conf.
The default Ubuntu document root is /var/www/html. You can make your own virtual hosts under /var/www. This is different to previous releases which provides better security out of the box.
Reporting Problems
Please use the ubuntu-bug tool to report bugs in the Apache2 package with Ubuntu. However, check existing bug reports before reporting a new bug.
Please report bugs specific to modules (such as PHP and others) to respective packages, not to the web server itself.
Valid XHTML 1.0 Transitional

From this file alone, we can get at least the following important information:

When access to the machine, the default entry page is/var/www/html/index html. Configuration system description in/usr share/doc/apache2 / README Debian. gz. The complete user manual can be downloaded by installing apache2-doc. The main configuration file is/etc/apache2 / apache2 conf. Startup and shutdown apache2 services can execute commands/etc/init d/apache2 start (stop/restart) but it can be service apache2 start (stop/restart). Remember this one! Remember! Add root permissions! There is no obvious hint (good pit) that root permission is not added here. When encountering problems, it is hard for people to think that it is the fault here, so please remember 1! Remember! Add root permissions! By default, apache2 denies access to files other than /var/www and /usr/share folders. This permission is controlled by apache2.conf files.

The default apache2.conf is:

# This is the main Apache server configuration file. It contains the
# configuration directives that give the server its instructions.
# See http://httpd.apache.org/docs/2.4/ for detailed information about
# the directives and /usr/share/doc/apache2/README.Debian about Debian specific
# hints.
#
#
# Summary of how the Apache 2 configuration works in Debian:
# The Apache 2 web server configuration in Debian is quite different to
# upstream's suggested way to configure the web server. This is because Debian's
# default Apache2 installation attempts to make adding and removing modules,
# virtual hosts, and extra configuration directives as flexible as possible, in
# order to make automating the changes and administering the server as easy as
# possible.
# It is split into several files forming the configuration hierarchy outlined
# below, all located in the /etc/apache2/ directory:
#
# /etc/apache2/
# |-- apache2.conf
# | `-- ports.conf
# |-- mods-enabled
# | |-- *.load
# | `-- *.conf
# |-- conf-enabled
# | `-- *.conf
# `-- sites-enabled
# `-- *.conf
#
#
# * apache2.conf is the main configuration file (this file). It puts the pieces
# together by including all remaining configuration files when starting up the
# web server.
#
# * ports.conf is always included from the main configuration file. It is
# supposed to determine listening ports for incoming connections which can be
# customized anytime.
#
# * Configuration files in the mods-enabled/, conf-enabled/ and sites-enabled/
# directories contain particular configuration snippets which manage modules,
# global configuration fragments, or virtual host configurations,
# respectively.
#
# They are activated by symlinking available configuration files from their
# respective *-available/ counterparts. These should be managed by using our
# helpers a2enmod/a2dismod, a2ensite/a2dissite and a2enconf/a2disconf. See
# their respective man pages for detailed information.
#
# * The binary is called apache2\. Due to the use of environment variables, in
# the default configuration, apache2 needs to be started/stopped with
# /etc/init.d/apache2 or apache2ctl. Calling /usr/bin/apache2 directly will not
# work with the default configuration.
# Global configuration
#
#
# ServerRoot: The top of the directory tree under which the server's
# configuration, error, and log files are kept.
#
# NOTE! If you intend to place this on an NFS (or otherwise network)
# mounted filesystem then please read the Mutex documentation (available
# at <URL:http://httpd.apache.org/docs/2.4/mod/core.html#mutex>);
# you will save yourself a lot of trouble.
#
# Do NOT add a slash at the end of the directory path.
#
#ServerRoot "/etc/apache2"
#
# The accept serialization lock file MUST BE STORED ON A LOCAL DISK.
#
Mutex file:${APACHE_LOCK_DIR} default
#
# PidFile: The file in which the server should record its process
# identification number when it starts.
# This needs to be set in /etc/apache2/envvars
#
PidFile ${APACHE_PID_FILE}
#
# Timeout: The number of seconds before receives and sends time out.
#
Timeout 300
#
# KeepAlive: Whether or not to allow persistent connections (more than
# one request per connection). Set to "Off" to deactivate.
#
KeepAlive On
#
# MaxKeepAliveRequests: The maximum number of requests to allow
# during a persistent connection. Set to 0 to allow an unlimited amount.
# We recommend you leave this number high, for maximum performance.
#
MaxKeepAliveRequests 100
#
# KeepAliveTimeout: Number of seconds to wait for the next request from the
# same client on the same connection.
#
KeepAliveTimeout 5
# These need to be set in /etc/apache2/envvars
User ${APACHE_RUN_USER}
Group ${APACHE_RUN_GROUP}
#
# HostnameLookups: Log the names of clients or just their IP addresses
# e.g., www.apache.org (on) or 204.62.129.132 (off).
# The default is off because it'd be overall better for the net if people
# had to knowingly turn this feature on, since enabling it means that
# each client request will result in AT LEAST one lookup request to the
# nameserver.
#
HostnameLookups Off
# ErrorLog: The location of the error log file.
# If you do not specify an ErrorLog directive within a <VirtualHost>
# container, error messages relating to that virtual host will be
# logged here. If you *do* define an error logfile for a <VirtualHost>
# container, that host's errors will be logged there and not here.
#
ErrorLog ${APACHE_LOG_DIR}/error.log
#
# LogLevel: Control the severity of messages logged to the error_log.
# Available values: trace8, ..., trace1, debug, info, notice, warn,
# error, crit, alert, emerg.
# It is also possible to configure the log level for particular modules, e.g.
# "LogLevel info ssl:warn"
#
LogLevel warn
# Include module configuration:
IncludeOptional mods-enabled/*.load
IncludeOptional mods-enabled/*.conf
# Include list of ports to listen on
Include ports.conf
# Sets the default security model of the Apache2 HTTPD server. It does
# not allow access to the root filesystem outside of /usr/share and /var/www.
# The former is used by web applications packaged in Debian,
# the latter may be used for local directories served by the web server. If
# your system is serving content from a sub-directory in /srv you must allow
# access here, or in any related virtual host.
<Directory />
 Options FollowSymLinks
 AllowOverride None
 Require all denied
</Directory>
<Directory /usr/share>
 AllowOverride None
 Require all granted
</Directory>
<Directory /var/www/>
 Options Indexes FollowSymLinks
 AllowOverride None
 Require all granted
</Directory>
#<Directory /srv/>
# Options Indexes FollowSymLinks
# AllowOverride None
# Require all granted
#</Directory>
# AccessFileName: The name of the file to look for in each directory
# for additional configuration directives. See also the AllowOverride
# directive.
#
AccessFileName .htaccess
#
# The following lines prevent .htaccess and .htpasswd files from being
# viewed by Web clients.
#
<FilesMatch "^.ht">
 Require all denied
</FilesMatch>
#
# The following directives define some format nicknames for use with
# a CustomLog directive.
#
# These deviate from the Common Log Format definitions in that they use %O
# (the actual bytes sent including headers) instead of %b (the size of the
# requested file), because the latter makes it impossible to detect partial
# requests.
#
# Note that the use of %{X-Forwarded-For}i instead of %h is not recommended.
# Use mod_remoteip instead.
#
LogFormat "%v:%p %h %l %u %t "%r" %>s %O "%{Referer}i" "%{User-Agent}i"" vhost_combined
LogFormat "%h %l %u %t "%r" %>s %O "%{Referer}i" "%{User-Agent}i"" combined
LogFormat "%h %l %u %t "%r" %>s %O" common
LogFormat "%{Referer}i -> %U" referer
LogFormat "%{User-agent}i" agent
# Include of directories ignores editors' and dpkg's backup files,
# see README.Debian for details.
# Include generic snippets of statements
IncludeOptional conf-enabled/*.conf
# Include the virtual host configurations:
IncludeOptional sites-enabled/*.conf
# vim: syntax=apache ts=4 sw=4 sts=4 sr noet

Notice the first paragraph:

<Directory />
 Options FollowSymLinks
 AllowOverride None
 Require all denied
</Directory>
<Directory /usr/share>
 AllowOverride None
 Require all granted
</Directory>
<Directory /var/www/>
 Options Indexes FollowSymLinks
 AllowOverride None
 Require all granted
</Directory>

This section makes it easy to know which folders apache2 gives open permissions to. Later you can achieve all sorts of ulterior motives by modifying this.

One last important configuration is the default directory change. The default directory is actually recorded in the file :/etc/apache2/ sites-available / 000-default.conf (there is also a link to him in /etc/apache2/ sites-enable /) :

myths@myths-X450LD:/etc/apache2/sites-available$ cat 000-default.conf 
<VirtualHost *:80>
 # The ServerName directive sets the request scheme, hostname and port that
 # the server uses to identify itself. This is used when creating
 # redirection URLs. In the context of virtual hosts, the ServerName
 # specifies what hostname must appear in the request's Host: header to
 # match this virtual host. For the default virtual host (this file) this
 # value is not decisive as it is used as a last resort host regardless.
 # However, you must set it for any further virtual host explicitly.
 #ServerName www.example.com
 ServerAdmin webmaster@localhost
 DocumentRoot /var/www/html
 # Available loglevels: trace8, ..., trace1, debug, info, notice, warn,
 # error, crit, alert, emerg.
 # It is also possible to configure the loglevel for particular
 # modules, e.g.
 #LogLevel info ssl:warn
 ErrorLog ${APACHE_LOG_DIR}/error.log
 CustomLog ${APACHE_LOG_DIR}/access.log combined
 # For most configuration files from conf-available/, which are
 # enabled or disabled at a global level, it is possible to
 # include a line for only one particular virtual host. For example the
 # following line enables the CGI configuration for this host only
 # after it has been globally disabled with "a2disconf".
 #Include conf-available/serve-cgi-bin.conf
</VirtualHost>
# vim: syntax=apache ts=4 sw=4 sts=4 sr noet

The value of the "DocumentRoot" key is the default directory, and we can change it as we like.

The simple configuration of apache2 is basically these, do not need baidu, we are also completely clear.

Note:

Remember to restart the service after you modify the configuration file You can change the page by setting the permissions of /var/www to 777

conclusion