Apache HTTP Server (httpd)

Apache is a robust, modular web server. While Nginx leads in raw performance, Apache leads in flexibility via .htaccess. v2.4 remains the stable standard in 2025.

When to Use

• Shared Hosting: .htaccess allows per-directory config without restarting the server.
• Dynamic Modules: Loading modules without recompiling.
• Legacy Apps: Many PHP/Perl apps are pre-tuned for Apache.

Core Concepts

MPM (Multi-Processing Modules)

• prefork: Compatible with non-thread-safe libraries (old PHP).
• event: Modern, async I/O. Best for high concurrency.

VirtualHosts

Serving multiple domains from one IP.

.htaccess

Files in the web root that override config. Convenient but slows performance.

Best Practices (2025)

Do:

• Use event MPM: It rivals Nginx in connection handling.
• Disable .htaccess: If you have root access, put config in httpd.conf Directory blocks for performance.
• Use HTTP/2: Enable mod_http2.

Don't:

• Don't enable unnecessary modules: Reduce attack surface.

References

• Apache HTTP Server Documentation