How to see which modules are active in Apache

In this manual, you will learn how to identify which modules are active on your Apache HTTP Server using the terminal. It is a quick and fundamental process for administration, debugging, and advanced configuration tasks.

Prerequisites

Before starting, make sure of the following:

• Have terminal access to your server.
• Have administrator permissions (root user or with sudo).
• Have Apache installed on the system.

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1. View active modules on Debian/Ubuntu systems

In Debian-based distributions, you can list the currently loaded modules with the following command:

apache2ctl -M

What does this command do?

• apache2ctl: Apache control tool.
• -M: shows all modules loaded in memory.

This list includes static and dynamic modules active at that moment.

2. View active modules on Red Hat / CentOS systems

In Red Hat-based systems, the equivalent command is:

httpd -M

Details

• httpd: the main binary of the Apache server in these distributions.
• -M: lists the currently loaded modules.

3. View all available modules (Debian/Ubuntu)

If you need to see all installed modules (active or not), you can check the corresponding directory:

ls /etc/apache2/mods-available

Useful information

• This directory contains all the modules you can enable or disable.
• Active modules are usually linked in /etc/apache2/mods-enabled.

4. View all available modules (Red Hat / CentOS)

In Red Hat distributions, you can check the available modules with:

ls /etc/httpd/mods-available

⚠️ Note: In some versions of Red Hat, modules can be found in paths such as /etc/httpd/conf.modules.d/.

Final recommendations

• Use grep to filter specific modules:

  apache2ctl -M | grep rewrite
  

• Always verify changes by restarting the service:

  systemctl restart apache2   # Debian/Ubuntu
  systemctl restart httpd     # Red Hat/CentOS