Cheat Sheet #day3 - Apache Web Server

Apache Web Server Cheat Sheet

Basic Commands

• Start Apache:

  sudo systemctl start apache2      # Debian/Ubuntu
  sudo systemctl start httpd        # CentOS/RHEL
  

• Stop Apache:

  sudo systemctl stop apache2       # Debian/Ubuntu
  sudo systemctl stop httpd         # CentOS/RHEL
  

• Restart Apache:

  sudo systemctl restart apache2    # Debian/Ubuntu
  sudo systemctl restart httpd      # CentOS/RHEL
  

• Reload Configuration:

  sudo systemctl reload apache2     # Debian/Ubuntu
  sudo systemctl reload httpd       # CentOS/RHEL
  

• Enable Apache on Boot:

  sudo systemctl enable apache2     # Debian/Ubuntu
  sudo systemctl enable httpd       # CentOS/RHEL
  

• Disable Apache on Boot:

  sudo systemctl disable apache2    # Debian/Ubuntu
  sudo systemctl disable httpd      # CentOS/RHEL
  

Configuration Files

• Main Configuration File:

  /etc/apache2/apache2.conf         # Debian/Ubuntu
  /etc/httpd/conf/httpd.conf        # CentOS/RHEL
  

• Virtual Hosts Configuration:

  /etc/apache2/sites-available/     # Debian/Ubuntu
  /etc/httpd/conf.d/                # CentOS/RHEL
  

• Enabled Sites:

  /etc/apache2/sites-enabled/       # Debian/Ubuntu
  

• Modules Configuration:

  /etc/apache2/mods-available/      # Debian/Ubuntu
  /etc/httpd/conf.modules.d/        # CentOS/RHEL

Enabling and Disabling Sites

• Enable a Site:

  sudo a2ensite example.conf        # Debian/Ubuntu
  

• Disable a Site:

  sudo a2dissite example.conf       # Debian/Ubuntu
  

• Activate Changes:

  sudo systemctl reload apache2     # Debian/Ubuntu
  

Enabling and Disabling Modules

• Enable a Module:

  sudo a2enmod module_name          # Debian/Ubuntu
  

• Disable a Module:

  sudo a2dismod module_name         # Debian/Ubuntu
  

• Activate Changes:

  sudo systemctl restart apache2    # Debian/Ubuntu
  

Common Directives

• DocumentRoot: Specifies the directory out of which Apache will serve files.

  DocumentRoot /var/www/html
  

• ServerName: Sets the hostname and port that the server uses to identify itself.

  ServerName www.example.com
  

• Directory: Controls the settings for a specific directory.

  <Directory /var/www/html>
      Options Indexes FollowSymLinks
      AllowOverride None
      Require all granted
  </Directory>
  

• Listen: Specifies the port that Apache will listen on.

  Listen 80
  

• ErrorLog: Sets the name of the file to which the server will log any errors it encounters.

  ErrorLog ${APACHE_LOG_DIR}/error.log
  

• CustomLog: Sets the filename and format of log files.

  CustomLog ${APACHE_LOG_DIR}/access.log combined
  

SSL Configuration

• Enable SSL Module:

  sudo a2enmod ssl                   # Debian/Ubuntu
  

• Default SSL Configuration File:

  /etc/apache2/sites-available/default-ssl.conf  # Debian/Ubuntu
  /etc/httpd/conf.d/ssl.conf                      # CentOS/RHEL
  

• Common SSL Directives:

  SSLEngine on
  SSLCertificateFile /etc/ssl/certs/your_domain.crt
  SSLCertificateKeyFile /etc/ssl/private/your_domain.key
  SSLCertificateChainFile /etc/ssl/certs/chain.crt
  

Access Control

• Require Directive:

  <Directory /var/www/html>
      Require all granted
  </Directory>
  

• Allow/Deny Directives:

  <Directory /var/www/html>
      Order allow,deny
      Allow from all
  </Directory>
  

• IP-based Access Control:

  <Directory /var/www/html>
      Require ip 192.168.1.0/24
      Require ip 10.0.0.0/16
  </Directory>
  

Useful Commands and Tools

• Test Configuration:

  sudo apachectl configtest           # Debian/Ubuntu
  sudo httpd -t                       # CentOS/RHEL
  

• Check Apache Status:

  sudo systemctl status apache2       # Debian/Ubuntu
  sudo systemctl status httpd         # CentOS/RHEL
  

• Log Files Location:

  /var/log/apache2/                   # Debian/Ubuntu
  /var/log/httpd/                     # CentOS/RHEL
  

This cheat sheet provides a quick reference to the most commonly used Apache web server commands and configurations, helping you efficiently manage your server.