1. **What is a Web Server?**
1.1. **Common Web Servers:**
1.1.1. **Nginx**
1.1.1.1. **What is Nginx?**
1.1.1.2. Request Flow: Nginx and PHP-FPM
1.1.1.2.1. 1. **Client Sends Request:** A client sends an HTTP request to the Nginx server.
1.1.1.2.2. 2. **Nginx Receives Request:** Nginx receives the request and forwards it to the PHP-FPM process manager.
1.1.1.2.3. 3. **PHP-FPM Spawns Process:** PHP-FPM spawns a new PHP process to handle the request.
1.1.1.2.4. 4. **PHP Process Executes Script:** The PHP process executes the PHP script.
1.1.1.2.5. 5. **PHP Process Sends Response:** The PHP process sends the generated HTML response back to Nginx.
1.1.1.2.6. 6. **Nginx Sends Response to Client:** Nginx receives the response from PHP-FPM and sends it back to the client.
1.1.2. **Apache HTTP Server**
1.1.2.1. **What is Apache?**
1.1.2.2. Request Flow: Apache
1.1.2.2.1. 1. **Client Sends Request:** A client sends an HTTP request to the Apache server.
1.1.2.2.2. 2. **Apache Receives Request:** Apache receives the request and processes it.
1.1.2.2.3. 3. **Apache Spawns PHP Process:** Apache spawns a new PHP process to handle the request.
1.1.2.2.4. 4. **PHP Process Executes Script:** The PHP process executes the PHP script.
1.1.2.2.5. 5. **PHP Process Sends Response to Apache:** The PHP process sends the generated HTML response back to Apache.
1.1.2.2.6. 6. **Apache Sends Response to Client:** Apache receives the response from the PHP process and sends it back to the client.
2. Understanding PHP-FPM
2.1. **What is PHP-FPM?**
2.1.1. * **FastCGI Process Manager for PHP:**
2.1.1.1. **Why Do You Need PHP FastCGI Process Manager?**
2.1.1.1.1. * **Performance:** Optimizes PHP execution.
2.1.1.1.2. * **Scalability:** Handles increased traffic.
2.1.1.1.3. * **Resource Utilization:** Efficiently utilizes system resources.
2.1.1.2. * **Key Features:**
2.1.1.2.1. * **Improved Performance:** Optimizes PHP execution.
2.1.1.2.2. * **Scalability:** Handles increased traffic.
2.1.1.2.3. * **Flexible Configuration:** Customizable settings.
2.1.1.2.4. **Resources:**
2.1.1.2.5. * **Process Management:** Manages PHP processes efficiently.
3. **Popular Web Server:**
3.1. * **Key Features:**
3.1.1. **Modularity:** Extensible with modules.
3.1.1.1. * **Resource:** Official Apache HTTP Server Documentation: [https://httpd.apache.org/docs/](https://httpd.apache.org/docs/)
3.1.2. **Flexibility:** Highly configurable.
3.1.2.1. * **Resource:** Official Apache HTTP Server Documentation: [https://httpd.apache.org/docs/](https://httpd.apache.org/docs/)
3.1.3. **Security:** Robust security features.
3.1.3.1. * **Resource:** Official Apache HTTP Server Documentation: [https://httpd.apache.org/docs/](https://httpd.apache.org/docs/)
3.1.4. * **Virtual Hosting:** Supports multiple websites on a single server.
3.1.4.1. * **Resource:** Official Apache HTTP Server Documentation: [https://httpd.apache.org/docs/](https://httpd.apache.org/docs/)
3.1.5. **Resources:**
3.1.5.1. * Linux Tutorial: [https://ubuntu.com/tutorials/install-and-configure-apache](https://ubuntu.com/tutorials/install-and-configure-apache)
3.1.6. * **URL Rewriting:** Manipulates URLs for SEO and dynamic content.
3.1.6.1. * **Resource:** Official Apache HTTP Server Documentation: [https://httpd.apache.org/docs/](https://httpd.apache.org/docs/)
3.1.7. * **Error Handling:** Customizes error pages.
3.1.7.1. * **Resource:** Official Apache HTTP Server Documentation: [https://httpd.apache.org/docs/](https://httpd.apache.org/docs/)
4. **High-Performance Web Server and Reverse Proxy:**
4.1. **Key Features:**
4.1.1. **High Performance:** Efficiently handles a large number of concurrent connections.
4.1.1.1. * **Resource:** Official Nginx Documentation: [https://nginx.org/en/docs/](https://nginx.org/en/docs/)
4.1.2. **Flexibility:** Highly customizable configuration.
4.1.2.1. * **Resource:** Official Nginx Documentation: [https://nginx.org/en/docs/](https://nginx.org/en/docs/)
4.1.3. **Reverse Proxy:** Masks the origin servers from clients.
4.1.3.1. * **Resource:** Official Nginx Documentation: [https://nginx.org/en/docs/](https://nginx.org/en/docs/)
4.1.4. **Load Balancing:** Distributes traffic across multiple servers.
4.1.4.1. * **Resource:** Official Nginx Documentation: [https://nginx.org/en/docs/](https://nginx.org/en/docs/)
4.1.5. **Reliability:** Robust and stable.
4.1.5.1. * **Resource:** Official Nginx Documentation: [https://nginx.org/en/docs/](https://nginx.org/en/docs/)
4.1.6. **Caching:** Stores static content to reduce server load.
4.1.6.1. * **Resource:** Official Nginx Documentation: [https://nginx.org/en/docs/](https://nginx.org/en/docs/)
4.1.7. **Resources:**
4.1.7.1. **DigitalOcean Tutorial**: [https://www.digitalocean.com/community/tutorials/how-to-install-nginx-on-ubuntu-20-04 ](https://www.digitalocean.com/community/tutorials/how-to-install-nginx-on-ubuntu-20-04)
4.1.8. **SSL/TLS Termination:** Encrypts and decrypts traffic.
4.1.8.1. * **Resource:** Official Nginx Documentation: [https://nginx.org/en/docs/](https://nginx.org/en/docs/)
4.1.9. **Gzip Compression:** Reduces transfer size.
4.1.9.1. * **Resource:** Official Nginx Documentation: [https://nginx.org/en/docs/](https://nginx.org/en/docs/)